I am wondering when Bob will be available to play in matchmaking by everyone.
Welcome to the forums!
Since you are new, I suggest to take a look at this thread as it will help you find your way around and also to get familiar with the community guidelines:
That said, Bobby currently has too many issues and the devs are making sure he is up and ready to play with everyone else as soon as they are fixed.
You can follow their progress on this trello board here: https://trello.com/b/D8JlQGll/evolve-stage-2-feature-bug-roadmap
P.S. If you want, you can play Behemoth offline now to already try him out and get a good feeling for when he becomes available later on.