You don't put your bags out the night before. Instead, you get off the ship with all of your luggage with you. I did this once in a similar situation with an early flight. I made it to the airport with a huge amount of time to spare! Had I known that, I would have stayed on board for breakfast!
Carnival Victory (Canada): August, 2006
Carnival Liberty (Eastern Caribbean): January, 2008
Carnival Pride (Mexican Riviera); August, 2008
Carnival Freedom (Western Caribbean): January, 2009
Carnival Legend (Western Caribbean): June, 2009
Carnival Spirit (Alaska): August, 2009
Carnival Victory (Southern Caribbean): January, 2010