Whenever I've made them, I use glass, but that is just basically because we have it and its there. But I really don't see that there would be much of a difference, as long as you grease (or whatever) before hand.
And as far as 9" vs. 9.5" pan goes, I really wouldn't worry about it. It would probably still turn out the same, but the 9.5" pan might make it a little less deep than a 9" pan would. The same recipe and principles still work.