Ultimately, I think it's up to the parent to judge whether or not it is safe for their kids to do certain things independently. Maybe society was less complicated back then, but I started walking to school by myself at 7 (that was back in China). I also free roamed around the neighborhood with my cousins and played in different playgrounds, soccer fields, or on farm lands. When I moved to Canada at 9, I was taking the bus to movie theatres; I also took the bus to hang out at my buddy's house (he lived pretty far away). I grew up ok and didn't get murdered.

I think having a sibling or a friend to go out together really helps; at least that gave me a lot of peace of mind. My daughter and son are born close together, so they started walking to school together every since my daughter was 9, son was 8. They also started taking the bus with their friends to the local mall when my daughter was 11, my son was 10. Last summer, my son and his buddy really got into biking, and they started to bike all around the neighborhood and even biked to the local mall and back. My kids are also still fine and have yet to be murdered.

Kids can become very capable, very independent, if you train them and allow them to be. And I think kids being independent is really good for them.