I'd say it's technically "gen 9", if using the parameters of a NINTENDO console succeeding the Wii U. In the dynamic of the larger gaming industry picture, I suppose you could make the argument that it's sort of a gen 8.5, as it's similar in horsepower to the PS4/Xbox One and competing basically directly with them.
But honestly, at this point we may as well just throw out the numbers, as they've pretty much become meaningless, seeing that the big three are no longer close to synchronized in their console releases. This essentially has led to "relative" definitions of what constitutes a "generation" which means there's no longer any point.
The only stable or consistent factors are the console generation within the specific company's timeline and what's it's competing with at its time of release.
"We hold these truths to be self-evident - all men and women created by the, go-you know.. you know the thing!" - Joe Biden
