Okay, so I was watching X-PLAY on G4 and so I decided to look online at their website to see if it said anything about Kingdom Hearts. I search it I found out they had something about Kingdom Hearts: 358/2 Days. It had the release date. It's release date was on the website October 1, 2009!
The link if you don't believe me. The website also has videos, pictures, and news about the game.
Apparently it's September 29 in U.S. and October 2 in Europe.