We lived up on a farm so was too far to walk to school. We used to catch the bus.
Ds catches the bus home from kindy, there is a teacher on board and the bus drops them at your door. They include a school bus service to and from school when ds starts year 1 so he won't need to walk but if I was faced with it.... Nope I wouldn't let him walk on his own until probably 10yrs old at least. Not necessarily him that I don't trust, there's lots of crazies about and unsafe drivers. Just never know what could happen!