Answering the OP's question: "is Bonaire worth it for a solo trip if I plan on doing guided shore dives" I would say, no.
With the exception of the excellent diving on the east side of Bonaire (White Hole/Turtle City) and certain sites around Klein Bonaire, I found Bonaire fairly lackluster.
If you are sold on spending money for guided dives (given that you describe yourself as a new diver, I think that is both a wise and mature use of money), there are much better options in the Caribbean.
Bonaire's attraction -- diving wise -- is not the diving itself (I'll come out and say it, I think it sucks) but the freedom from a schedule structure, the ability to do your own thing, and the relative cheapness of self-guided shore diving. If you are not taking advantage of that, IMO Bonaire is not worth it.