At 7 my dd got a sports scholarship to go into year 3.
Her main sport was swimming, and she was racing against 11/12 year olds and winning.
Unfortunately you cannot compete in swimming competively until you are 9, but you can do some inter clubs etc.
She had to do a days trial of different sports, and if it was sports that she hadn't done before they wanted to see how she picked it up.
Whichever sport she does she excels at. She had to do the beep test and had to perform at a standard of a 12 year old.
I would take that then that for a 9 year old to be scholarship material should be matching 13/14 year olds.
If you are a sports scholar expect to have not many hours in the day left for anything else:
Swimming 25 hours a week training
Gymnastics 18 hours a week training
Team sports 2 hours a day training - matches on Wednesday and Saturday afternoons
Independent school was the only way to fit it all in - up at 5am to start the day.
Main thing is child has to be passionate about it and have the drive to put in all the time.
My other children are equally as taleneted sport wise, but have absolutely no desire to put in the hours, therefore they won't be going for sports scholarships.