You can be virtually certain that he will become non violent if you do the taming work with him. But even so, some igs are nasty for life. This is fine if you want a display iguana. And, a few igs calm down after a time of bad behavior, but there is no way to predict it.
It also can be caused by your ig having become more familiar to you, and stops the fear-driven behavior of holding stock still or maniacally running around inside his cage when your hand goes in. The next step in his growing confidence in you is to attack you ( he's no longer convinced you are about to kill and eat him).
I've been attacked by grown igs, and we all want you to be careful and not let him freely attack. My worst attack was from an ig who was standing on the carpet in front of my feet, while I lounged way back in my easy-chair. This ig snapped into attack mode, jumped on my legs,, and ran up my body to get a bite on my face. I have a creepy feeling he was going for my eye. He was unbelievably quick, so my instinct to raise my arm to fend him off came a little late, and he bit my cheek as I was pushing him away, plowing several deep tooth cuts on my face. I never let him get the drop on me again.
Iguanas are born with the instinct to drive strangers and other iguanas away from their territory. They often use tooth and claw to do that. Protect yourself, never let him get that close to you again, and when he stops near you and gives you eyeball service, toss a bath towel over him.
A proactive thing you can do is to pick him up and hold him for 15 minute stretches. When you first grab him he will fight and alligator roll like crazy, but that is over in 30 seconds. Hopefully he will soon notice that you are a 100 degree heater, and comes to like laying on you.
Oh crap there is too much to say.