I find generations to be a funny topic. Video games have so many aspects that are not fully understood or universal due to the secretive nature of the big video game publishers.
The SEGA Dreamcast released in 1998 when the n64 was in 1996. Different generations.
The DS released 4 years after the gameboy advance and in the same a year as the psp and the power difference between the two was staggering. The wii was far behind the 360 and ps3 but they are the same generation.

I had a similar discovery with the term 2nd party. A group of wildly different people couldn't figure out what they think it is. Is a 2nd party game able to be 2nd party if it's made by a major company or does it have to be a smaller company, what the hell makes it a 2nd party studio? Why do we have this term when it's not releveant in film or tv as everything is outsourced there.
The endless weirdness that exists in video games and their terminology.

Here's a pretty good video on it and even they are struggling with console generations after a lot of research and planning in making their video.
https://www.youtube.com/watch?v=IEeEROc0bY8

Switch is ninth generation. If it were a home console only, it would be the second eighth generation console for Nintendo. Basically like the Atari 2600 and Atari 5200 in the second generation and the Sega SG-1000 and Sega Master System in the third generation. Switch as a hybrid puts it in a different generation from the Wii U, and the fact that it is also a successor to the 3DS. The leap between the 3DS and Switch is staggering.
Even if Switch 2 launches in 2023, it'll likely just be an early tenth generation console.

I think the concept of multiplat gens is in itself obsolete now. So I think of the Switch as either Nintendo's first hybrid console or Nintendo's 7th home console overall.

My take...

(1) Not only is it not a 9th gen console (its 8th gen), (2) its not even a "home console" in the traditional sense. Its a handheld.

The reasoning behind my conclusions....

1. I believe console generations are defined by the period a console s released in and also, in turn, by the games it shares with other platforms. Usually, of that same period too.
   
   The NS was released in 2017, just a little over 3 years into the life of the 8th gen consoles. Gues in a manner of speaking that makes it an 8.5 gen console... However, I also expect that the NS would get even fewer ports of PS5/XSX (9th gen) games than it's currently getting of the PS4/XB1 games. This would mean that its multiplatform library of games would consist mostly (I reckon over 90%) of 8th gen titles. 
   
   If the bulk of your software is 8th gen, then you are an 8th gen console. 
   
   
2. And as I have been saying since it was launched, the NS is not a Home console. Its a handheld console. Simple as that. The NS is as much a home console as if we take a PSP or PS vita and plug it into a TV. You do not need a dock to use the NS, but you cannot use a PS4/5/XB1/XSX without a separate display. 
   
   This is made even more evident by Nintendo releasing the dockless NS lite. Also something I predicted Nintendo would do before the NS was even released. Furthermore, this is also why it exists in a vacuum, its sales have no bearing on those of the home consoles and their sales have no bearing on it. More accurately though, its doesn't actually exist in a vacuum, its selling and tracking like a handheld. It's even priced like one.

But most people would rather compare it to the PS4/XB1 and in a few months to the PS5/XSX... when absolutely nothing about it suggests that it should even be compared to those platforms. But hey, if we can't then it would make for some really boring sales charts because it's competing in a handheld space all on its own.

More proof of this? let's say you planned on buying a console in December 2019. Now list out 15 of the most popular multiplatform games released between 2017 and 2019. Chances are, only like 3 or 4 of them actually are on the Switch. Which would mean that if you bought a switch, you are forgoing at least 10 of the games you actually had in that list. People by the Switch primarily for Nintendo games. No one buys a switch because they wanted to play Doom.

Wii had the hardware power of a GC and it was 7th gen. Why would anyone be bothered by the fact that Switch is 9th gen?

Noo. When ps5 launches switch will be alnost 4years? So 4 years into a older genn means its next genn?

Also switch is a hybrid,its both console and handheld some people should stop saying its not.

I doubt anyone is really bothered by anything. 

For me, its not about how powerful or when a console was released. It all really comes down to the games.

No one really grades a platform on when it was released or even how powerful it was, they grade it on which games you can or were able to play on it.

This is why MS can (claim to) be gen neutral now because they are building an ecosystem that would make which box you have under your TV irrelevant. Be it an XB1, XSX, XSS or PC... you can play all the games on their platform either locally or streamed. They are basically trying to create forward and backward compatibility.

Granted, if game streaming doesn' takeoff as well or isn't in every region that you can buy an xbox then this plan of theirs falls flat, but in theory/principle, its their end game.

Sony, and I believe Nintendo, is firmly rooted in generations. And that is the only reason stuff like this still matters.

So... if or when you can play your PS5/XSX games on your mobile phone while away from home as long as you have an internet connection, does that make them hybrids too?

And what would you call the Switch Lite, a hybrid? How? And what happens if a year from now Nintendo removes their software lock on it and releases a cable that allows you to connect the switch lite to a TV?

The switch is handheld. That can also happen to be connected to a TV. Calling it a hybrid is like Callin a galaxy phone a hybrid because it has Dex. Or calling a laptop a desktop/hybrid because you can connect it to your TV using an HDMI cable.

Why IS it a handheld, because every single witch console comes with all you need to game on the go with it in your hands. You DO NOT NEED a TV at any point in time to get the switch working or gaming.

I guess you can call it a hybrid because you can "choose" to use it while tethered to a TV. But in truth that's more a QoL feature than something that is contingent to being able to use the Switch. I'll say again, the Switch Lite is physical proof that the Switch is a handheld. There is no need for new made-up names or qualifiers, there are a lot of things out there that can do more than one thing, but if you look closely (hell not even closely just look honestly) you can clearly see what that thing really is or what its primarily designed to do.

Its like everyone just forgot that even the PSP had AV cables too that allowed connect it to your TV. Does that make t a hybrid too?

Is it a console or handheld though? I mean those sales include the version which is handheld only..
Personally I don't think it can be included in the same category as Xbox and PlayStation.

I'm not sure if you guys are aware but "Next gen doesn't start until Sony says it does". That's a rule. You can Google it.