Mario Tennis, Mairo Golf, Mario Kart, Mario Party, Mario Baseball and (maybe) Mario Strikers are all in seperate canons from the actual series. It is said in Paper Mario that Mario and Luigi used to have kart racing, playing tennis and golf, but I seriously doubt the kart racings were about throwing mortal explosives to each other. In Mario Party, the goal is basically to hurt your friends the most possible, yet I doubt Mario would hurt Peach. In Mario Kart, we see Baby Mario, Baby Luigi, Dry Bowser and Rosalina appearing, but that's quite impossible considering Dry Bowser IS Bowser, Baby Mario and Baby Luigi can't go to the future and Rosalina wouldn't quit her job of "mother of the cosmos" to have fun.
And it continues. So the Bowser from spin-offes (excluding RPGs) is NOT the Bowser from Super Mario 64 or Super Mario Galaxy.