It's a real short list if you want to stay with SSI: Maui Dive Shop. They're the only SSI facilities on the island.
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They have a shop at Kahana Gateway Mall between Kaanapali and Kapalua. They rent everything you need. They also have a shop in Lahaina Gateway Mall but their shop in Kaanapali is just a kiosk so they don't rent dive gear there.
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If they include boat dives with their cert dives or you decide to dive with them later - they have a big boat moored at Ma'alea Harbor so you'll need the car.
If you get a referral to a PADI shop - which all the others on the island are - you'll possibly be issued a PADI card from that instructor. And probably have to do some residual skills checkouts first. All of which takes time/costs more.
After you're certified, I recommend Lahaina Divers for beginning divers in West Maui. They have the largest boats and will dive either Molokini or Lanai - the two signature dive areas. They put a DM in the water for every 8 divers and you'll be grouped with any other new divers.
They also do escorted shore dives most afternoons on demand. So does Tiny Bubbles Scuba nearby. One of the better shore dives in that area is Kapalua Bay - Kapalua Divers does that as an escorted dive also.
Another easy entry dive nearby is Kahekili (Old Airport) Beach. It's shallow for a really long way out. Used to be a sugar cane loading station so to the south in about 20' there's some debris left over - look in the pipes, bottles etc. for Octopus.
Later in the week maybe drive down to Wailea and dive with Maui Dreams Dive Co. or Shaka Divers - some of the better dives are in that area. Wailea Beach would be an easy entry dive that gets good near the south point at about 40'. You'll see puffer out there, humuhumu.... triggerfish and occasionally a Manta Ray glides by. Makena Landing is pretty simple to access also. Go really early for parking - like 6-7am if you can. Especially on the weekend.
Should you decide to strike out on your own to shoredive, you'll need to tow a flag - it's the law. I've never seen anyone check in West Maui but I have seen the DLNR agents at Wailea and Makena Landing.
I assume at least your son is going to have the Jr. OW designation so all the dives I've mentioned have a lot to see above 60'. He'll also be able to dive inside Molokini Crater easily if you go out there with Lahaina or one of the Kihei operators. I can't remember the depth at the Cathedrals off Lanai but newer divers do them also. I did my first time on dive #12.
Sheraton Black Rock could be another easy dive in the Kaanapali area - it's been years since I was there. There's been a recent change in tank availability from the on-site operator - I believe they only rent to guests now. So check with one of the other dive operators when you're there to see how to access it. You can also go in from the north side if someone shows you how - the gear drop is actually just off the golf course.
I'm going to suggest you pass on Olawalu this time. Tiger Sharks are occasionally seen there. You're not their prey but it can be a little disconcerting to see a 15' shark cruising nearby.