Admission to Pearl Harbor Memorial is on a first come first served basis. They give out so many tickets for every 10 minutes, when all the tickeys are given out they are done for the day. You may land at 7am , but I wouldn't count on being ashore in 10 minutes.
You then need to do something with your luggage. No bags of any kind are allowed in
the memorial grounds for security reasons and knowing that everybody locks everything in the trunk of their cars, apparently theft from the cars has becaome a problem.
So, if you get off the ship quickly, get rid of your bags, get over to Pearl Harbor and are lucky about it being a relatively quiet day you can probably do it.