Sorry to hear what your going through, as has been said, yes it's definitely a case of overreacting, but certain points, such as your sons adhd, will trigger red flags in the system due to previous cases of exploitation of vulnerable people, even if your sons background criteria doesn't fit those previous high profile cases.
What I will say is social services are probably one of the most lazy & corrupt organisations in existence, & I would hate it if the fact that you are trying to encourage your son to pursue his interests in a controlled safe manner, is likely to be used against you.
To that end, you need to audio record all meetings with them, preferably with some sort of concealed professional device, rather than relying on a phone which can go wrong or be disrupted.
You'll need to do this covertly, SS will never voluntarily agree to recorded meetings, & will immediately leave meetings should this be discovered.
Unfortunately their reports tend to be written in a piecemeal fashion, in order to discredit or malign those they're working against, so you need to protect yourself as a family with solid proof of what's said during these meetings, which you'll need to save & possibly document for future reference.
If you fail to do this, at the very least you'll find your son railroaded on to the "at risk register", or worse.