Amy,
The instructions for IRS Form 5405 (available at http://www.irs.gov ) state, "This is the date you purchased it (or the date you fiirst occupied it if you constructed your main home)". If you had the house built and didn't move in until January 1 or later, you cn claim the 2009 credit.
All tax prorations are based upon the closing date per the HUD-1.

Good Luck,
Dennis.Anderson@Century21.com

Amy..

Wow.. what a question. I know you're hoping for the deed transfer date, but I would almost be positive it's the date you take possession which would be closing date. Sorry to burst your bubble. You were so very close.

God Bless,

Josh

You need to consult your accontant but I would say date of closing.