For our cruise, I did exacty what you want to do. I dropped off my DW , DS, and DD right at the terminal with all the luggage. My DW took ALL the tickets and went inside to check ALL of us in. I drove the car back to the Radisson/AVIS and took the shuttle back to the terminal. Actually, we stayed at the Radisson the night before and I was able to leave our car there during the cruise.
When we got to the terminal, they checked my name against their list of passengers and looked at my driver's license.
When I got into the terminal, my DD was waiting (while my DW and DS stood in line to board). DD told me the check-in person wanted me to go to her counter (I was to skip ahead in line to the front) and "show my face." She did not hold back my KTTW card. That was it. Then, my DD and I joined my DW and DS in the front of the line to board (well, about ten people from the front).
It was the best way to do it. No problems at all.
Remember to do the same thing in reverse when you get back (if you're staying on in Florida). My family waited with the luggage outside the terminal while I took the shuttle back to the Radisson/AVIS, got the car and then drove over to the terminal. No problem getting in. It's so much easier getting a spot on the shuttle if it's just you with no luggage. No hassles carrying the luggage across the parking lot to where the shuttle meets you.
Good Luck.
