For Maui, I have had good experiences with B&B Scuba out of Kihei. It looks like a lot of the dive scene is on hold due to the fire that wiped out Lahaina. Not sure when you'll be here on your cruise, but going out of Kihei to Molokini Crater is a wonderful dive.
On Oahu I second Island Divers Hawaii out of Hawaii Kai. Their afternoon dives do the shallower reefs and are wonderful.