Bud is shown to be a regular tough guy most of the times, and will use violence to solve problems, which didn't work on Geo. He also seems to be more independent in the anime, but still follows Luna around.

When Geo first went to school, he was jealous of Luna showing Geo around. When Taurus attacked Omega-Xis, he coincidentally found Bud and forced an EM-Wave Change. Fortunately, Luna's comments left him unguarded and Taurus Fire was defeated, leaving Bud no memory of what happened.

Bud, along with Zack and Luna, saw with their own eyes that Geo is Mega Man and the existence of Omega-Xis. However, only Luna refused to believe it, until the end of the Tribe series, and even then only to herself.

(Source: Mega Man Knowledge Base)