Worst game I've played this year had to be Star Wars: The Force Unleashed. Maybe it's because I waited until 2009 to try it, but that game is not aging gracefully. Oh, also its a terrible brawler.  I think I played maybe 2 hours of it boxed it up and returned it for credit. On the plus side, the 10 dollars of credit I got back was used to upgrade my Dragon Age: Origins to the collectors edition.
 
The worst game released in 2009 however, would have to be Scribblenauts. I was so disappointed, the execution of all its parts just didn't work. I wonder how different the game would have been had it had D-pad functionality for movement? I surely hope the game worked as a proof of concept however, I'd like to see a second attempt.