Q: Family sharing child under 13

I have recently set up Family Sharing for myself, my wife and my 12 year old son.  All fine so far apart from the annoying disappearing notification of an app download request from my son. If I am not looking at my phone at the time of the request, I will have nothing visual to let me know he has requested to download an app.  The only work around I have found is by physically checking notifications by pulling down the screen.

Anyway, my question is - Once my son turns 13 will he be able to download apps without requesting my permission  and is there a risk that he can spend my money downloading paid apps and in app purchases?