I was on a flight that landed at 11:00 and was onboard and eating lunch at noon. I will say although, it was the quickest time getting onboard Allure of the Seas, we literally walked on. They also did your sign/sail pic right there at the desk, so no waiting in line for that. They also had 4-6 different different photo opts before getting onboard, so it was also easy to skip that.
What ship are you cruising on?