Your longest wait of the morning is likely to be the security line at the airport.
You eat breakfast and immediately afterwards should be able to exit the ship - figure you're off the ship between 8:00am and 9:00am.
Locate your checked luggage, proceed to customs line - approx. 10 minutes.
Stand in line for customs - 10-15 minutes.
Walk to bus - 1 minute
Buses are constantly loading and departing, so as soon as your bus fills, you're on the way to the airport - allow 15-20 minutes, but it should be less than that.
Bus ride to MCO - allow 1 hour
Regardless of this time clock, the cruise line recommends against (and we agree) a flight departure time prior to Noon. We just got off the Fantasy Preview Cruise a few weeks ago. We were on the early breakfast seating (breakfast at 7:00am) and had a Noon flight (exactly). It worked very well. The wait at the airport was not all that long, but there was enough leeway in case of delay that we had a relaxing morning. Why re-enter the stress of the everyday world sooner than necessary?
Co-Author, PassPorter's Walt Disney World, PassPorter's Disney Cruise Line, and PassPorter's Disneyland and Southern California Attractions