I have not cruised the Hawaiian itinerary *YET
But I can give you some in general tips about cruising.
Take post it notes! You will need them to give messages to your cabin steward, and also to keep track of each other while on the ship. We tried walkie talkies with our children, but they turned them off by middle of the first day. We resorted to checking in at the room every three hours, they had to leave a post it note with their whearabouts for us if we hadn't seen them. They will LOVE the teen program and other kids that they meet. The program keeps them constantly busy. Make sure your kids go the first night to the meet and greet and again to the activities the next day...after that, they may decide to just hang out with some of the kids they met rather than going to the organized activities.
Take swimsuits and gear in a carryon rather than leaving it in your packed luggage. The pools are ready as soon as you are onboard, but your luggage may not arrive for several hours. This way, once you get your room key, the kids can change into their suits and have fun in the pool before sail away.
Excursions, Im not sure how many day's you're going for, but that does sound like alot. If you are used to being on the go at that pace though, it's probably going to be a blast! We usuallly book two excursions on a three port cruise, the third city we just walk thru the port city on our own shopping and exploring. My husband prefers spending one port day, on the ship, rather than going sight seeing at all...he likes having the pool area to himself, and there are discounts on spa services on those days.
You will have a great time and I look forward to hearing your trip review upon your return! Just remember to go with the flow : )