For an 11:15 flight, even with pre-check you need to be at MIA about 10:00. The ride from PE to MIA will take about an hour, so that translates into off the ship, with bags, and clear of customs/immigration by NLT about 8:45.
As Bruce said, you can make it but it will be stressful. Do you want to spend your cruise worried about making your flight home? I would find a flight leaving early afternoon but it's your call.