We've been down with our kids of similar age. When mooring, we always look to be near a spot the kids can have fun snorkeling near the boat - often we'd take the mooring ball closest to shore, reef, etc.

Also, our kids really liked the SUPs - heavily used. Kayaks not so much. They liked to paddle in and order 'virgin mudslides' (a.k.a. milkshake ).

Great suggestion on educating them on the use of dingy. Our kids enjoyed being the dingy captain and shuttling to/from boat.

Also, fishing off the boat at night is always a big hit with kids - you'll never know what you will catch. Suggest going with barbless hooks to make release easier.

Enjoy.