If one feels so inclined, buy him and release him. The ocean is where he belongs.
If he keeps for 2 years it will be because he's stunted as those fish need lots of space to swim (they go up to 40 feet a second) and turn around. Making him adjust to living in an 8 x 2 or 8 x 3 tank for 2 years is not doing him any favors.
Release it in the ocean... summer times coming, waters are warming up and he should not have a problem making his way down south
I think you are set on buying it and just want some approval on here to make you feel better
I do agree that releasing him into the ocean when he's a bit bigger is a good idea.
Releasing them is illegal - and a bad idea regardless of the law. Being in a controlled environment has exposed him to pathogens not in the wild. Also, chances are it has seen some type of medication. Usually, that type of thing will inhibit the immune system's ability to fully function if he were put back. There are huge protocols places have to follow prior to introducing a captive animal back to the wild.
Why not just contact an aquarium that can house them and see if they will take him now? We have great barracuda at or aquarium in a 500k tank. They do need a huge chunk of space. While they do hover in one spot here and there they do swim around quite a bit. I would also check the legalities behind this animal in your area before you do anything with it.
This. Prior to taking him home, call your aquarium. Many places won't take donated animals that have outgrown a home tank purely for the idea that it only encourages people to continue to buy them since they have an 'easy out' at the end of their mistake.
That being said, I have raised plenty of 'cuda in grow out situations for large displays. They do get big, but like posted, they hover/hang out. Not big swimmers unless they are chasing prey. With a 600 gallon (assuming you don't build some goofy verticle size), you'll have a year or two with the fish...if not more.