I doubt he's mooning over Hawaii...he's wild caught and so not used to captivity. You can choose to acclimate him and keep him or find him another home.
I think it's obvious you can't send him back to Hawaii.
The most likely scenario is you give him to someone else who keeps him.
That relieves you of caring for him, but it does not address your expressed concern that he wants to be free.
If you want to own a chameleon, then make peace with the one you have. Make his environment as friendly as possible. You'll find this board a great resource for that.
If you do not, in fact, want a chameleon, then decide what you want to do. If it's to get the chameleon out of your hands, the easiest answer it to find someone who will take it off your hands. You've already had offers here. You can certainly find an owner for it.
If you want to set the chameleon "free" you would be better advised to travel to a location where they are already surviving and set it free.
http://www.californiaherps.com/lizards/pages/c.jacksonii.html
Note that I am not advocating that, I'm simply suggesting that letting it go in a place where the species is known to survive is less of a death sentence than some other options.