As a kid I walked or rode to and from school from 8 normally in the company of the neighbours kids (who were my age) and/or my sister but I did it alone often enough.
As for wandering the streets, I was 12 when I was allowed to do that, with a curfew of 8pm in summer. I just had to let mum know.
In the area we live in now I wouldn't be letting my kids do that til quite a bit older I don't think. There are lots more main roads and traffic.

