Re: Changing My Sons Last Name in Texas
Begin with a paternity suit at the courthouse where the child lives. You'll need to legally establish paternity. Whether or not the court will accept the paternity test results you have is up to the court. You may need to take another one.
After paternity is established, you may petition to have the child's last name changed, but with the child being 9, you may want to be open to having a hyphenated last name.
If you wanted babies all to yourself, you should have created them by yourself. Until you do that, children have the right to BOTH parents, especially since you found them suitable to procreate with.