You can check-in early at the terminal (9:30ish) and then go have lunch on the Queen Mary on in downtown Long Beach. They will assign you a boarding group and give you a time to return. When you come back you will wait with your group to board.
All I ask is a tall ship and a star to steer her by; John Masefield
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012, Dream 2013
Celebrity: Summit 2011
Princess: Ruby 2010, 2014, Caribbean 2013, Coral 2014, Regal 2014, 2016
Star Clippers: Royal Clipper 2015