Roosters crow. Some crow ALOT. I had a silkie roo named Roger, HE was very aggressive at first, then his hormones chilled out, and he turned into one of the best roosters and daddy. Even raising chicks on his own after a raccoon killed all the other chicks and hen in the coop he was in. So, maybe he just needs some time to get it right. The next question, is he agressive to you, or to the hens? Might just be that he's learning to mate, and it is not pretty at first. Looks and sounds awful at first, but then they get the hang of it and its, nothing.
Wow, that is aggressive. Roosters can do that, especially when they've been handled a lot. They can be so sweet, and cuddly and then BAM! Hormones hit and they become the ultimate jerk. If he is aggressive to you to that point, I'd cook him. If you can't, find an Asian person, or a Chineese person who would like him. OR, you could put your big girl pants on, go in the run with the intent to catch him, don't be scared, well don't show that you are, and snatch his fuzzy butt up and hold him upside down. Put your foot on him, not to hurt him, but not to let him up, and hold him down... re-exert that you are the boss. As far as he is concerned, he's the boss. If not, then I do hope you can find a new home for him with lots of silkie girls.