The only book that has received major changes in that time frame is Physics. For 2011, they fixed all of the errors and addressed all of the complaints they got (like a weak EM section). You'd be fine with the 2009 versions of the other books.
Thanks. I ended up ordering the new books anyways as I want to ensure that there is no writing and marked answers. Plus, it seems that the resell value is fairly consistent from year to year so at most I expect to lose the shipping costs. 🙂