I'll be traveling alone to Bonaire, I hope in October.

Is it difficult to find a dive buddy there?

Not in the least if you are on a boat. In fact the dive master will pair up unattached divers. It is then your choice whether or not to buddy up for the rest of your visit with that person, or to try for a different buddy. If you plan on shore diving, it may be a little harder to find someone to match your interests and skills.