Not unless your other hardware devices use the same hardware components it won't. If the NX has a custom GPU for example from anything inside of a Galaxy phone for example, you can't just "port" Mario Kart 9 to it. 

It's like saying someone could "hack" the XBox One and quickly run PC apps like Word, Office, on it because it does run Windows. Well yeah ... except the hardware is very different in actuality and the version of Windows the XB1 uses is heavily customized. 

Or vice versa, someone should be able to "hack" a PC since it runs Windows just like the XB1 does to be able to run XB1 games on the PC ... it isn't that simple. 

Modders can do anything and android is so open source unlike windows that porting over games from the NX to Android Devices will be easy as pie.

I don't  think the problem is som much of people emulating the games on other Android system, but people hacking the NX and playing pirated games on it. Like the PSP, the problem was not the emulators of the system on PC and other devices, the problem was the PSP itself was so easily hackable people bought the system, patched it and never bought a game. Emulation is inevitable for all systems, but it usually appears years after the system is no longer supported (people is still trying to emulate PS360 on their computers, with no success).

A certain member had a vision about the future of Nintendo and I remember reading it back then and hoping it would be true. Maybe it is?

Ouya really is not a good comparison, it's literally just a $99 Android box, now if it were a $99 box with the full support of Nintendo than it would be a lot more appealing.

Huh? No. If Nintendo games rely on Nintendo hardware it won't work. Yes, you can hack everything but rewriting major parts of the code is not as easy as pie.

If you root an Android phone you can easily "Trick" your phone into thinking it has a different GPU ( especially common when Tegra 3 chips had games which where optimized for it). I'm sure modders can release some software which tricks Android phones into thinking they have that special Nintendo hardware and booom Nintendo NX games are playable any android phone!

This, for instance the original Xbox OS was a modified version of Windows 2000 and Dreamcast OS was a modified version of Windows CE. And yet you couldn't play either Xbox or Dreamcast games on PC.

But what does the game do if it calls a function which is not present on your rooted device? Crash? Seg-fault? Do nothing? Jump out of window? You also can't trick your phone (if it's arm) to be an intel and expect it to execute x86 code, no matter whether it's rooted or not.

Android will be most likely only the base for the NX OS. I doubt it will be fully compatibel with android devices.

Nintendo use android because they don't want to create a new OS for NX from ground up. To build a full new OS would be very complicated and time wasting , because consoles OS are much more complex these days than two gens before.

So Nintendo use a free OS like android as the base and creates their own libraries (graphic system, input system) on top of this.