I don't have any experience with the FNP9 or the SR9, but there are a lot of good choices out there. Check if any of your local ranges rent handguns. If possible, rent and shoot as many as you possibly can before making your decision. What's right for someone else, may not be right for you. If renting is not possible, then at least go to your local shops and hold as many as you can and see how they feel. 9mm is a great choice for cheap practice, and is good for self-defense when loaded with hollow-points. Good luck. The hunt for the right handgun is always fun.
Welcome to the forum.