No child in kindergarden should walk home without an older child or adult with them. Period. It's borderline neglect. Would you leave a kindergarden child at home alone while you ran to the grocery store? No? Then you don't let them walk to and from school alone. That's insane.
8 years old is too young too. Its borderline. It depends on the kid, the community and the roads.
8 years old is too young too. Its borderline. It depends on the kid, the community and the roads.