Fulton's does not accept DDP. Planet Hollywood does (it is not on the 2009 list yet because it is not owned by Disney). Never heard that they have lobster. Except for various appetizers that include lobster (California Grill had one for instance - but those can't be purchased with the regular dining plan, you must have the deluxe) the only DDP restaurant that currently serves lobster is Narcoosees - which is indeed a 2 credit restaurant.
Based on past years, I'd assume that Planet Hollywood is going to accept DDP in 2009 and Fulton's is not.
If you are not using DDP, you can also get lobster at Shula's and Bluezoo (both are at the Dolphin).