+1 for Mike Severns recommendation, they are probably the best dive op we have been out with anywhere. Also highly recommend going from Kihei, it's well worth the drive even if you are staying in Lahaina. The time you save getting to Molokini means that you are on the dive sites ahead of all the big boats out of Lahaina with many divers, much less crowded. Mike Severns will also drift the back wall of the crater, it's an awesome dive, we were there in June a couple of years ago & you could see the shelves on the wall 120 feet down from the surface. Lots of pelagics around the wall when we were there.
If you haven't been to Maui before, one suggestion if you are staying in Lahaina, you may want to rent a car at the airport. You'll save a lot of money by getting one there for a week vs rentals in Lahaina & if you want to explore around a bit it also makes it easy to get down to Kihei to dive. Have a great trip!