I agree with the exercise comment.  Of my daughters nine year old friends, those who are carrying excess weight are exhibiting breast buds first (in fourth grade).  Our endo told us at one of the first appointment to encourage all the exercise possible since many CAH girls will have weight issues.  But from what I have read in the MAGIC newsletter it is not uncommon for CAH girls to experience precocious puberty.  We are happy that our daughter has held off this long, but won't treat her if she enters it from this age on since it is not that uncommon in the schools to start budding around 9.