It used to be 14 or 15 years of age, a young player would sign schoolboy forms, basically contracting themselves to the club until they were 16, where a decision would be made on whether or not they'd be given an apprenticeship until they were 18. I think that they could still play for their local club until they were 16, then join the professional environment, although i had to give up my local team at 14 and play for the youth team.
Picking players up at 9 has got to be a precarious situation, it must be a numbers game. I'm struggling to work out how a nine year old would be coached, based on brain development and physical development. How can a coach refine a nine year olds natural ability?