You can play the wii version through the wii U console. It is fully backwards compatible BUT the Wii version isn't half the game the Wii U version is. I bought the Wii version for my son at Christmas and we started to play it but noticed that there were certain elements missing. They were kind of like, it looks like something is supposed to be here but isn't??? So I checked into it and sure enough there was content missing from Wii version versus the Wii U version but somehow the price was the same ? I wasn't too happy so I returned the Wii version, bought a Wii U and the Wii U version and WOW. The graphics aren't in the same realm and there are many things present that were not in the Wii version.
If it were me, I'd buy the Wii U version of the game and try and sell the considerably poorer Wii version.