Her dad and I were never married. I have primary custody. He has not paid any child support in about 9 years and has not seen her in 7 years. I have no idea where he is. How do I get sole custody?

File at your county family court. It's a process.

Fist it sounds like you have full custody, if you have custody, and physical custody, what does the absent father have? visitation rights?

Why is he not paying child support, has he been turned over to child suppot enforcement?

But you can hire an attorney and go back to court and try to take away more of his rights, visits, he will be served and have a right to defend of course.