What do you think about how Sonic wanted Nine In Green Hill so Nine would make more friends while Nine wanted Sonic in The Grim so Sonic would have less friends?
Nine definitely has a possessive streak but I don't think his goal was ever to isolate Sonic specifically so he'll have less company. He just didn't care about the rest of Sonic's friends in the same way he doesn't care about anyone but Sonic
For Nine, isolation has most likely always equaled safety, since if there's no one around, no one could hurt or bother him. Sonic happened to be an outlier case in the fact that even once Nine was going a bit mad with god powers, Sonic still struggled to really physically hurt him, let alone do it out of nothing but pure malice, presumably like everyone else Nine had the misfortune of coming across. In fact, Sonic saved Nine's life whenever he could and generally remained concerned for his wellbeing throughout all of their escapades. So Nine craved his companionship above all else while, unfortunately, still under the framework of wanting to be as far removed from everyone else as physically possible because that was his ultimate fantasy. Only accepting Sonic by his side because he was literally nice
Sonic, on the other hand, is a rather social guy that has no problem making friends of anyone, his enemies included. He saw how lonely and cynical Nine was and decided the best way to fix that was by introducing him to more friends and a kinder environment of his world, so he got it in his head that once they manage to restore green hill, he'll make damn sure to introduce Nine to his life back home, completely disregarding the potential consequences or how literally impossible or unlikely it would actually be. Not unlike coming across a traumatized stray kitten and being all like Oh Sweet Little Baby You're Coming With Me.
Just unfortunate that never came to pass hah
