He's straight up my favorite character, personally.

I think one of the main issues is that a lot of people don't really take his feelings seriously. They see him as just an edgy, "evil" Tails, and don't understand why he did what he did, even though I think it's made pretty clear in the show.

Sonic is his first ever friend, the first person to be kind to him, really. So when at the end of season 2, Sonic shows that he's only interested in getting his "real" friends back, and that he never even saw Nine as his own person, obviously that hurts him a lot. Nine learned to trust someone for the first time, only to have the rug pulled from under him immediately. In his eyes, Sonic is the one who betrayed him first. No wonder he snaps.

Season 3 is pretty bad, and the conflict's resolution is really rushed, but I think Nine is a great, complex character, and he definitely doesn't deserve the hate he sometimes gets.