All parrots naturally vocalize in the morning and evenings, and cockatoos are among the loudest parrots out there. It really doesn't sound like he's doing anything abnormal right now, just growing up and stretching his vocal cords

The key is to make sure normal vocalizations don't turn to inappropriate attention screaming. Vocalizing is a brief period of screeching in the morning or evening, usually only continues for a couple minutes (a couple ear splitting minutes that seems like hours lol) and the bird stops by itself. In nature, vocalizing is a way of contacting the flock and making sure everyone made it through the night or made it back to the roost. Behavioral screaming is persistent, happens at all times of day, and is typically resolved only when the bird gets what it is screaming for (ie, attention, food, getting out of the cage ect...). It does not sound like your bird is behaviorally screaming right now, but you need to be careful not to accidentally encourage him to start by giving him extra attention when he vocalizes. He will just learn screaming gets attention. Leave him alone while he vocalizes.
Growing up, my parents 3 parrots were like alarm clocks when they woke up, and certainly let us know when they felt it was time for bed. Out of the 3 (2 amazons and a goffin cockatoo), the too' was by far the loudest. I mean, he was literally 5x louder than the zons, and he was a small breed of cockatoo. I cannot imagine how loud a U2 must be! However, noise is a part of owning parrots, and with time you learn to tune it out (or maybe you just start going a bit deaf lol). In a few years, you won't even be bothered by the am/pm vocalizations anymore. BTW, I like how you put that- "getting the wild out", I think anyone with a parrot can relate to that
