Do it.
We took our boys (10 and 13) on a whim while driving home last summer, and it certainly made an impression.
The aquarium is good, but honestly I thought the TX aquarium in Corpus was better. I would rather have spent that time at the WW2 museum, which is one of the best I've ever seen. We could probably have done two full days there. If we'd planned ahead better, we would definitely have done Preservation Hall.
We had an absolute blast embarrassing the shit out of them one evening on Bourbon street. They learned what vomit mixed with fecal/urine slurry and MD 20/20 smells like, and my wife made our older one get his picture taken in front of all the titty bars, then had them pose with a guy in leather hot pants, a crop top, and a cowboy hat.
At breakfast at Cafe Du Monde the next morning, the 10yo pointed wide-eyed at the newspaper headline that said 3 people were shot on that corner later that night.
It was pretty awesome.