I don't have access to the '09 manual right now, but here's a thread from 2008 referring to your question:
http://forums.usfirst.org/showthread...ht=bumper+zone
If the game manual does not specifically define BUMPER ZONE, then I would suggest you pose the question on the official Q&A before you decide to really do this. In 2008, bumper articulation wasn't allowed due to that Q&A thread, and I'd imagine there will be something similar in 2009 (though you have to ask for it to be official). It's a gray area, and you'd rather ask ahead of time and be told 'no' rather than be told 'no' by the head ref at a competition.