Upgrading 7 speed MTB to a 9 speed? and...?

Ok so I'm upgrading shifters so I thought I might as well upgrade to a 9 speed. I measured the spacing for the rear wheel and I got 134.5mm.... Now, is this enough spacing to fit a 9 speed, or better yet a 10 speed cassette?.... Now concerning the derailuer hanger. Are all made to fit the same way on any MTB? Or do I need an specific model for the type of mounting that I have?