Hi L.,
My daughter (now 10) is also active, and has always had difficulty winding down to sleep at night and staying asleep. We have a variety of strategies, most of which she needs to be reminded to use, including relaxation techniques (tensing then relaxing muscles, starting at the toes and moving up), reading before turning out the light, a 1mg tablet of melatonin before bed (Whole Foods sells one that the child can put under their tongue if they can't swallow pills yet), having Mom or Dad lay down with her and cuddle for a few minutes (this can be her time to talk about things that are on her mind but that she is reluctant to discuss in other contexts). White noise (we use a fan and/or air cleaner) is helpful, and she also has a "sound machine" which plays soothing sounds. Another factor is making sure that she has had enough physical activity every day, because that helps her get to sleep.
My daughter is also precocious and has had many issues that could not be resolved with "conventional wisdom" advice, such as the tried and true "bedtime routine" advice to solve sleeping problems. I know how frustrating this can be. I have to keep looking for solutions and trying different things. Then once I think I have a problem solved, she comes up with a new problem! Augh. This is draining. Other mothers of active, precocious girls are invaluable to me, because it helps to know I am not alone in my struggles. Good luck to you. She is surely a treasure, even if a lot of work!