I don't know Nos Krusero personally but they're right off Playa Kalki which is one of the better dives IMO.
Go West Diving at All West must be pretty close - otherwise the other Go West shop (where they keep the boats) is just a mile or so north of there at Lodge Kura Hulanda - not by distance but by road. I recommend them also, good shop, nice people, convertible tank valves if you dive DIN.
It's good you're getting a car since there's about 6-8 restaurants in the area and everything else is a drive back towards town.
Landhuis Daniel on the main road near town is pretty highly recommended also - poolside dining.+1 for Sunshine -
Sol Food - I think she's still only open Fri-Sun though so check.
Also buy food b4 you drive out - stop at Centrum Market - there's not a lot of market options farther west. I'm pretty sure this is it -
Centrum Supermarket Mahaai | Facebook
As you leave the airport there's a rotary - the first right is to Westpunt, the 2nd is Piscadera - take it and within a stoplight or two Centrum will be on the right. Maybe 2? miles. If you pass the Convention center you went too far.
They have used styro boxes on top of the the freezers for the drive out - like $2 each. Let the kids carry your stuff out and load it and tip them a few bucks - some sort of teen jobs program. Cost-U-Less is nearby also - IDK it.
Some divers like
All West Apartments in Westpunt - the other Go West shop is there. The bigger one is their shop at Lodge Kura Hulanda in Westpunt - good dive at either place but lots of stairs at All West. Although pretty much everything in that area is 50-60' or more above the beach including Nos Krusero.
I thought Marazul had a different dive operator but things change.
You won't find a lot of other dive operations in that area. For your wife - if you go out on a dive boat (you should to Watamula at least) - if she goes in off the Lodge KH "beach" - to the west there's flounder she can chase in the shallows under the cliffs the lodge is on. Completely safe, although Lodge guests do kayak near there.
Another good option is Playa Jeremi - one of the better dives and the north side of the cove is on Frommer's top 10 Snorkels in the Caribbean list from a few years ago - probably due to all the orange cup corals at the base of the cliff. I don't snorkel but I did there while waiting for my friends. Bring everything - one of few sites with no facilities
On the south end of the island the Tugboat dive site is pretty famous. The better part IMO is the deep wall around the south point but the boat itself is 17' deep near one of the coral covered pilings just off the end of the beach. The cruise lines do their snorkel excursion there.
Some of this is old - for example Sunset Waters is gone but I guess the dives are still there - also there seems to be a shop or not at various times at the Tugboat. . Playa Lagun is a pretty decent dive also - not sure if it'd be a great snorkel though. There's a nice beach, a few covered tables and Bahia Apt's Bar/Grill is the balcony you see perched on the west side of the cliff. There should be turtles there out thru the cove entrance since the fishermen clean fish there.
The Carpile wreck sites are what they sound like - there's two in different areas. That's actually another good dive - Trunk Bay/Varsenbaai - has Trunk Bay Divers on site. Your wife should snorkel just east of the beach in 6' of water for the turtles eating in the grass - been there forever - or under the dive dock for squid.
If you dive south, follow the reef edge and maybe 10? mins. south there's the pontoon boat wreck used to drop the carpiles - it's pretty flat on top but stuff is living underneath it. The cars themselves are deeper down the wall there - we didn't go there so IDK exactly where. Also at the start of the dive we found seahorses a few feet off the mooring ball but it was years ago. Trunk Divers sells a Curacao Dive site book.
There's a second Carpile dive at Pierbaai beach in east Willemstad. And a Dolphin
dive at Ocean Encounters/Sea Aquarium further east. It's over $200 now and not a wild encounter since the dolphins are used for shows at the Aquarium. The dive itself is done off the breakwater about 5mins. out by boat. Watch the dolphins go streaking overhead till you get to the site.
Superior Producer is the wreck on Curacao. It's in Piscadera but the cruise port traffic goes by it so only dove at night or when no ships are in port.
Relaxed Guided Dives is on the main road west a little past the airport. They have a tank/fill rental program although so does Go West. Discover Dive at the entrance to Playa Lagun has a truck height tank loading dock also but it's a little south for you. Check with Nos Krusero - they probably have somebody - possibly even with free delivery. Although many of the beaches are also dive sites with dive shop, food, etc. on-site. We did about 1/2 our dives with the onsite operator and half with our hauled tanks but there were 7 of us so we rented a 2nd truck just for tanks.
Some of this is old but still useful.
Scuba Shore Diving Site Listing for: Curacao, ABC Islands Curacao also has a pretty serious
Lionfish eradication progam so maybe contact them for places they need help.
I wrote too much...my buddy's wife is an ex-Curacao dive guide and they visit her mom often so we know a lot about it besides the 10 days we spent there a few years ago.