We were there Jan 1 with our 11yo and 8yo. We bought trolley tix and also went to the aquarium. A couple of notes if you do the trolley - don't buy the trolley tix via
DCL in advance. You'll get charged "Disney adult" prices for the 10yo children. When you get off the ship, you'll literally walk right past the trolley ticket stand, and they never sell out of tickets b/c it's a hop-on/hop-off thing. I wanted to play it by ear so I didn't buy a groupon in advance or anything, assuming I could do so on my phone when we were there, but I had spotty service. DH and I enjoyed the trolley narration for the history, architecture, plant info, but my kids thought it was boring. We actually didn't even make it all the way around. I consulted the map and we hopped off, walked to a different stop nearby that was closer to the end of the route, and rode it back to the beginning. YMMV but my kids wouldn't want to do it again. I think I oversold it b/c the "trolley" was pretty much a bus, which wasn't that exciting to them either.
They both really enjoyed the aquarium, which is right on the water. It's small, but it's SO close to the ship and easy. They had sting-rays, a touch pool, rescued sea turtles, etc. The sea turtles were the most interesting part for my kids, reading about how they lost a flipper, etc. It was more personal than other aquariums we've been to, and I wasn't expecting much b/c we used to live near the National Aquarium in Baltimore, but we all enjoyed it. We were there maybe an hour, hit the attached gift shop for souvenirs, grabbed an espresso nearby, and headed back to the ship after a quick stop at CVS for prosecco.
Don't overplan, whatever you do. My kids thought it was too hot. On Jan 1! And we currently live in Phoenix. The humidity is something! We didn't stay ashore nearly as long as I originally planned.