As he grows older, the more habituated to his environment he becomes, and learns more about you, and becomes less afraid of you. He may be acting out on impulses he was too afraid to show before. So, cleaning his cage now is not the same for him as it was then.
I have to assume that the previous cleanings were not comfortable to him, but he was too timid to display his displeasure. Lucky for you and him, he only tail-whips. I always treated those as if they were involuntary actions like sneezing, and tried to totally ignore them.
I would go ahead and pick him up maybe 3 times/day, whether he whips or not, and even if he starts to open-mouth gape or even bite. Do this now, while he is too small to really hurt you. Never let him escape from your hands. With confidence, reach into his cage and quickly grab him without letting him start a chase. But if he runs rapidly back and forth, bashing his snout, withdraw and wait for him to calm down. Then do it again, but faster. It's better to never let him win a chase. Grab him, and press him into your clothing until he stops struggling, which lasts 30 seconds or less. Sit down and hold him just firmly enough to keep him from escaping your grip. I would stop petting his head. It's common for tame and un-tame iguanas to stress over that, and they typically close their eyes to lessen the experience. But many end up liking it. Don't stroke his body, and be as unobtrusive as possible while you are holding him. You want him to have the mildest possible experience, as far as it concerns you. Try to ignore the intensity of his reactions. Ten minutes of holding is good for now.
Try to get him to accept treats, like bits of banana, apple, half-grapes, melon, blueberries, strawberries, etc. If he becomes motivated by any treats, you can use that to deepen your connection with him. At first, while you have him out, just lay a bit of treat next to his head, using long thin tongs or chopsticks, to keep your hands away from his face. Even if he doesn't eat it, he will become used to it's fragrance, and is likely to start eating them within a month. Then he can slowly come to associate treats with you, and with handling.
Also give treats while he is inside his cage. If you have long thin tongs, or a sharpened stick with a treat impaled on it, you can put it next to him in his cage. The hope is, this won't trigger his "invading my private territory" defensive response. If it does, place the treat farther away from him. He will know it's there.
These are the first steps in taming your iguana. Let us know about his progress! :-)