Speed is important, but there are a ton of other things that are MORE important for a 9 year old pitcher to be concerned about! Instead of comparing her speed to other pitchers, she should have her OWN benchmark she is trying to improve. I honestly have no idea what my DD's fastball was at 12u, because I didn't own a radar gun. What we did make sure of was that her overall mechanics were sound. Yes, she was throwing hard, but the speed came from the sum of all the OTHER stuff she worked at.
If your DD is using good form, just keep working HARD on drills that improve explosiveness - multiple arm circle drills, distance pitching, leg drives etc. As she gets older, if she continues to maximize her explosiveness without sacrificing form, her speed will follow.