Well it takes some of us longer than others to learn. Nine years is a long time...I guess you are a slow learner huh? You know what they say about opinions...everyone has one. Here goes mine.
Good for your girlfriend and your mother for recognizing that turning your back on your son is causing you problems and suggesting that taking care of the matter might be helpful to you. Your initial motivation seems a bit selfish but who cares as long as you get motivated.
Several people have dogged you about waiting 9 years to want to be a part of your son's life. You should have been there from the start but you weren't and there is no time like the present to start making up for lost time.
First regarding the birth certificate. Call the office of vital statistics for the state he was born in. Ask them what you need to do to get your son legitimized. Tell them you have results of the blood test and a court order where you have been paying child support. They will tell you what you need to do to get your name on his birth certificate.
Secondly, your attitude toward the mother. It's very defensive and will get you nowhere. She may be afraid that your son will be exposed to your defensive attitude and that would be unhealthy. Face it, if you are going to have a relationship with him you are going to have to deal with her. The courts are going to be very interested in how willing you have been to communicate and work through the issue with the child's mother.
You are defensive because you feel guilty as hell. You don't want to talk to her because you feel guilty. You don't want to answer his questions because you feel guilty. Shame, guilt, anger and all those negative emotions have no place in a situation like this. A judge will be able to tell whether you have the best interest of your child in mind by the way you conduct yourself through the process.
Get yourself an attorney who will not turn it into a long drawn out, adversarily, legal issue. Have your attorney petition the courts for visitation. Show some regard for the child's feelings when the visitation is requested. If your mother has a relationship with the child suggest that visitation is supervised by her in her home. That will show concern for the child and a willingness to allow him to adjust to the idea. Get in to see a therapist so you can get your head in a place to handle all this and, on top of that be able to say to a judge that you have been trying to figure out the best way by going to therapy.
Get over who he is calling Dad or what he might call you. Dad is just a word, it is not a reflection of what kind of respect or love a child might feel. At this point it's about getting to know your son, not about what he might call you isn't it?
As for the questions he will ask...tell him people make mistakes and that you made a huge mistake and that you hope he will give you the opportunity to make up to him for the mistake you made. He is nine years old. I doubt seriously he will need to know more than that from you at this point. By the time he does have deeper questions hopefully you will have a relationship with him and will be more comfortable answering the questions.
Nine years is a long time to live without knowing your father. It's better than 18 or 25 or 30 or 40 years. Get in there now and by the time he is 40 years old you will have been a part of his life for the majority of his life.
