You are protective of her. You stated that you have no sexual thoughts about her. Pedophilia involves having sexual thoughts about children and acting upon those thoughts. Your care and concern about her is the opposite of pedophilia.
In the 1996 film Beautiful Girls, the 13-year-old character, played by Natalie Portman, is infatuated with her much-older male neighbor who is played by Timothy Hutton. He is flattered by her crush. He notes their age difference and in response, she asks him to wait for her until she turns 18. His reply: “…you know in five years you won’t even remember me… I am formed and you’re not and you still have changes to grow through, you’ll change…”
The infatuation of the nine-year-old is flattering but she is a child. By definition she is immature, despite your characterization of her being mature for her age. As she develops, she will grow and change and mature. In fact, she may not even remember you, just as Timothy Hutton predicted in the movie. In nine years, she will change dramatically. Your belief that she will grow up to be a beautiful woman, who will feel the same way about you when she turns 18, is fanciful conjecture. It is the stuff of movies and creative fiction.
While it is theoretically possible that fantasy will turn to reality, it is highly unlikely. Psychologically healthy people strive to be realistic in their thinking at all times. It is important for you to be realistic in your thinking and in your beliefs. In this case, you are not being realistic.
Realize that this is a fantasy, one which has no basis in reality. The sooner that you can recognize the truth about the situation, the sooner this problem will be resolved. If you continue to struggle with this issue, then you may want to consider seeing a therapist. The purpose of seeing a therapist would be to ensure that you are realistic in your thinking and to behave accordingly. Please take care.