I tried to do a search on this and got a spam website. Maybe you can provide a city name and I(or someone else) can do a yellow pages search?
Frankly speaking, Bob needs to grow up and take responsibility for the child he made with you. It is grossly unfair that Bob would leave both you and his child on the hook right up to the time (or even after) as to whether or not he is going to exercise his visitation. You have the right to know if he is picking up his child so you can schedule accordingly and your child should not be left on tenderhooks as to if he is going to see his father that week!
And if Bob was old enough to make a baby with you, he is old enough to talk to you about his visitation arrangements without asking for his girlfriend's permission. He needs to put on his big boy pants and put his gf in her place...letting her know that his kid was on the scene before she was and until or unless he marries her, his number one responsibility is to his kid, and NOT her. And if she can't accept the fact that he has to communicate with you for the best interest of his child, he needs to give HER the boot!
Now as to visitation. The visitation is with your ex, not his mother, his gf, his best friend, etc. He needs to communicate with you directly or, if he refuses to do that, he needs to go back to his lawyer and set up a document (signed, dated, and witnessed) authorizing someone else to communicate with you on his behalf. Otherwise, you have the legal right to ignore any unofficial communication coming from anyone else but your ex as they have no rights in this matter. In other words, do not let anyone pick up your son in place of Bob unless you have a document authorizing it. Otherwise, Bob could say later that you didn't make the child available to him (yes, parents play games like that) as the person who called about picking the child up could have lied or been unauthorized to make that arrangement!
You need to get your lawyer to write an official letter to Bob letting him know that as the visitation is his alone, that you will not accept any communications regarding that visitation with anyone else but him unless he provides you with a signed, dated, witnessed document authorizing it. And that you will need such a signed/witnessed document each time he has someone else other than him pick up his child for the visitation.
Also, at the same time, ask your lawyer to explain to you your duty regarding his visitation times. In most documents, there is some sort of notification required that a parent is going to execute his visitation and that if the notification isn't given by a certain date/time, that visitation is cancelled for the week. If there is such a notification in your document, you need to have your lawyer make reference in that in the letter and let him know that from now on, if Bob doesn't notify you on or before that date and time that he is exercising his visitation, that visitation will be cancelled. And also say that if he habitually refuses to pick his child up for the scheduled visitation, that it will be documented and brought before the judge as you will be asking for more child support to cover the increased time and expense of taking care of the child the two of you made (he won't like that).
Now as for do you have to let Bob take the child when he shows up late for visitation? Check it with your lawyer first but I believe no. Tell him I am sorry but that since he could not be bothered to pick up his child when he was supposed to, his child was forced to make other plans to fill in that time. Tell him that he has lost his visitation for that week by not showing up like that (he has no right to leave you hanging like that as you might have had plans of your own AND this is also a control issue on his part...he is showing you that he can do what he pleases with impunity...don't let him get away with it!) but that he is welcome to schedule for the following weekend.
As for contempt of court, tell the judge that you made the child available for visitation but his father did not pick him up when he was supposed to. He didn't even call his child to let him know but he shows up eleven hours late (document everything). Since you made your child available for visitation at the scheduled time and the father refused to execute such visitation at the appropriate time, there is no contempt. And your lawyer might point out gracefully to the judge that it isn't reasonable for the child's father to expect you to wait at home for the entire time of the scheduled visitation for the father to execute such visitation. I doubt the judge would think that is a reasonable expectation.
Addendum: yes, your son's father has the right to visitation but he has no right to show up 11 hours late and expect you to sit there waiting for him to pick up his child. And it is grossly unfair to the child to expect him to sit at the door for eleven plus hours. Children are live human beings, not property. If the father is more than three hours late without good excuse or calling, I think you will find that the judge will not expect you to sit there any longer but you are free to make other plans. And as Bob is entitled to 57 hours of visitation a week (2 days, 9 hours according to the schedule you gave), it is extremely unreasonable for anyone to expect you to stay at home that entire time until Bob decides to pick up his child.