Fiscal year sales, that's really hard to say. They say that they've bumped up production to about double, which may be rather hasty. But it should sell quite well during the holidays and still has some demand to meet before a stable baseline is set. I think 10 million by years end and 12-12.5 million my March 2018 seems reasonable enough.

9m... by end of year?

It's breaking records, right? I say 18M.

We've yet to see an actual baseline (other than maybe in Japan) but I would say 9 million at the low end and 12 million if it continues to perform well. The biggest question for me is Europe.

3DS started as overly expensive, and no games other than Ocarina of Time. Didn't get any good games for over a year after that. Still sold 14 million first year.

Wii U was overly expensive and didn't have any good games until Pikmin 3. Sold almost 4 million first year.

Wii launched with a new Zelda, was inexpensive, and had five good games coming within the first year. Eventually these games were delayed, but the first two years of the Wii saw Mario Kart Wii, Zack and Wiki, Smash Bros., Super Mario Galaxy, and Metroid Prime 3. Sold 14 million units first year.

Switch launched with a new Zelda like the Wii. Mario Kart has always been a system selling franchise, and MK8 Deluxe looks amazing. Tons of people that skipped over the Wii U will be getting a Switch for MK8. Splatoon sold 4 million units worldwide, which is absolutely insane, for a new IP, considering the low install base of 13 million Wii U's. Super Mario Odyssey will push systems too. Galaxy sold 11 million units on the Wii, and if Odyssey is as good it will push sales too.

Like the Wii Nintendo is busy putting out it's bread and butter franchises as quickly as possible for the Switch. Mario, Mario Kart, Zelda, and Splatoon all sell amazingly well, and are all coming in the first year. Like the Wii the Switch has managed to wow the general public with a unique feature.
If Nintendo can announce a new Poke'Mon, Animal Crossing, and Mario Maker for the Switch it will surpass XB1 first year sales.

So 8-9 Million by March 2018.

I think you forgot about MK7 and Mario 3D Land were relased during the holidays in 2011. 

How about 7 million? Seems reasonable.

If they show animal crossing, pokemon, pikmin 4 and some decent 3rd parties like MH, dark souls during E3, i estimate the switch to reach 15mil by march 2018

More than DS, but less than PS4

You've finally seen the light.