It is completely possible for him to energybend. People, not the Avatars, used to energybend but the knowledge died out. The only requirement is that he has a true heart and true mind which could mean anything. It doesn’t have to mean that the man must be pure or innocent like Aang.
TFP!Starscream gif is super appropriate. (Steve Blum plays both Amon and Starscream like a BAMF.)