Is there a conflict between versions 8 and 9 on the same (Windows) machine?
I need to start testing version 9 but don't want conflicts with v8 or CS3DesignPremium, and it's going to be a headache to try to fire up another machine and even more of a headache to configure a VM for test.
There are a couple developers in my office that were successful at installing APEX 9 with Acrobat 8 installed though and both versions work fine.
Good luck.