I tried deploying Adobe Reader 9.0 to several campus computer labs I manage. I am using roaming user profiles, but I don't have AppData redirected - it stays on the local hard drive.
I discovered that while Reader 9 works OK for Administrators, it crashes at startup for people with just regular "User"-level privileges. This problem goes away if I remove the annots.api plugin file. Has anybody else seen this issue? I've gone back to Reader 8.1.2 in the meantime.