Well, he's 9.8 yo. He has to walk 3 short blocks and cross 3 roads, a busy one on front of our house with the lights zebra crossing, one small one leading off a tiny roundabout (cars drive slowly there) and one close to school with a lollipop man.
Ex thinks it's not a good idea.
DS wants to walk by himself. I have initially followed him and he's seems to be very good about road safety.
Yesterday I cunningly said that I'll walk with him half way as I need to get bread and he said "ok, but I walk in front and you in the back' 
He needs some independance but I'm here every morning chewing my nails wondering whether he got to school ok.