It is also recommended you carry any medications in your carry on. You shouldn't have any problems if they are in their original packaging.
Personally, I like to get to the pier around 11:00-12:00pm. Occasionally there may be a wait, but most of the time I'm checked in and on the ship by noon. You can go up and eat lunch at the buffet on Lido deck and then start exploring the ship so you find where everything is located. It's amazing how many people don't give themselves a tour of the ship and don't realize what all is available to them. You will be handed a deck plan of the ship when you check-in or by the greeters when you board. If not, then you can pick up a deck map at the Guest Relations desk. Cabins won't be ready until around 1:00PM. Check your larger luggage with the porters on the pier and just take your smaller carry-on with you.