If you go with the cruise line dive to AKR, ask for Spooky Channel, it's about the best in that area. Don't worry that it's just offshore, the dive is actually done as a shoredive from private property also. It's a long mostly overhead obstructed swimthrough, my friends said when they came out on the reef wall at the end of the dive they saw turtles, rays, big groupers and barracuda within about 30 seconds of exiting the channel - they didn't know where to look first.
Another option is the RIMS dolphin dive at AKR. You'd just have time to do a single dive as it's more involved, you first do a gear check off the back of the boat, then out to Bailey's Key to meet the dolphins, then they follow you out to the dive site as you descend and wait for them to arrive. The whole thing probably took the better part of 2 hrs or more - longer if you buy/wait for the video. Depending on the dolphins mood, you get about 30-45 mins. with them including some up close time. For us it was only our group on the boat since we were there during the start of low season. It's about $130 pp. if that's a consideration.
CTD's boats leave at 9AM so that's out. Unless you wanted to do one dive in the afternoon only, there's a 1PM boat. But it might be more trainees/beginners. They also do a 2:30 dive but that would be pushing it to get back to your ship. They do small groups though - all our dives were the 7 of us plus sometimes 4 others.
The West End would be more fun to eat and look around after your dives, it's a crazy mix of bars, restaurants and shops. And it's on Half Moon Bay beach if you want to lounge on the beach afterwards but depending on the sand flea count, that's not always such a good option. A cab from the cruise port to CTD should be under $20 total - negotiate up-front as prices go up when your ship docks. They're small cabs so if you have a lot of gear, look for a van. That would be more like $10pp. Cabs congregate in front of CTD so getting back shouldn't be an issue.
At AKR, it's just AKR - their (large) gift shop and restaurant - plus the beach out on the Key. Which I've never seen.
There's also the Waihuka Shark dive - it's by the airport so near the cruiseport/Coxen Hole. It's one dive and would be considered more advanced due to currents. Pay attention to the descent/ascent part of the briefing. My friends really enjoyed it, they had calm water so were able to really get close to the sharks. The feed is a very minor part of the dive at the end so it's not like the canned dives you do in the Bahamas.
info:
Roatan Shark Dive
one option for cruiseline booking:
http://www.roatanshoretours.com/shark_dive.htm
hth,
