I agree with Dave. You're pushing the envelope, but you can do it provided everything falls exactly into place; ship arrives on time, no hiccups with customs, there's no problems getting off the ship early, no traffic tie ups, you can get to the airport by 10:00am, and you don't mind paying an exorbitant amount for a taxi (figure from $75 - $100).
Just make sure you notify the Purser's Desk that you want early-off (self-disembarkation) and keep your luggage in your cabin instead of placing it in the hallway the night before. Then be ready to get off about 1/2 to 3/4 of an hour after they dock.
If all goes well, you should be okay.