9 year old, how much independence

[NorthernMC]

I’ve been thinking a lot recently about how little independence I give DC compared to what I had. I was playing out from age 3 with my 5 year old brother watching me but lots of neighbours who we knew and in a big group of children the same age. My 9 year old doesn’t really play out but none of the neighbours kids do either. He plays in the front garden and sometimes a friend will play too but that’s it.
He goes for a walk alone around the block with only one small road to cross or down to the post box on the same street.
He won’t walk to school alone as always wants us to take him and to be honest I’d worry about him crossing the road outside school as it’s busy with people who can’t understand not to park on zig zags or do a 3 point turn in the school driveway regardless of kids. School is only on the next street.
He’s doing an activity that he could walk to his Grandmas house from but it would mean a 400m walk along a busy main road on the same side but crossing a small side street. It would be at rush hour. Would this be ok? He’s just 9.
How much do your kids do at this age? We live in a big town but a nice area.

[NeverRTFT]

We are in similar age and stage with DS.
For comparison his big sis became independent- as in line travelling to school or to meet friends locally- in year 6. We got her a basic phone.
DS at 9 wants all that independence but we are holding back until next year.
Use the time now to really drill him on road safety, stranger danger and what to do if an adult or bully bothers you, memorise parents' mobile numbers etc