I'm pretty sure any incidents would hit the media pretty quickly. That said, driving your kids to school seems to be much more common now than it was 20 years ago.
My girlfriend, who grew up in the UK, was amazed when she first witnessed the kids on public transport, but then the UK is an extreme case of overzealous protection. These days you apparently can't just pick someone else's kids up from school without special paperwork.
UK is an extreme case of overzealous protection
I was 12 when I first went there to visit family, and I went everywhere by myself (not 9 as the original, but still younger than the US parents would like).
As a tourist I found the way that the destinations were announced over speakers extremely useful, and every stop had maps of the public transportation, timetables, etc.
I'd say it's very likely a 9 year old local would have no problem whatsoever, and I wouldn't find it irresponsible (even less so in today's cell phone age).
I walk each day past a primary school and all kids arrive unassisted. There are however teachers welcoming them at the gates and one police officer at the road crossing. But other than that they are on their own.
In Japan, motorcar drivers actually seem scared of pedestrians. I have difficulty crossing the road. In my country you usually stand still beside the road and wait for the cars to pass (for an opening). Here if you even look like you want to cross the road at some point in the future, the cars stop.
Here is how I cross the road in Japan: I wait at a place that I want to cross, but I turn my body away from the road. That way they think I am just standing there and drive past (instead of awkwardly stopping, etc...).
A lot of Japanese people that I've talked to don't have driving licenses. One person specifically said that it was because she was afraid of hurting others. That is quite different from my country's SUV style entitlement.
In China there was a story about retired professor that took care of that - by striking the cars with brick.
Come to think of it, I didn't think there was another Greek HNer in London, this is definitely worth a beer. Drop me an e-mail, or come to the next HN meetup this Thursday.
I'll send you some sun!
http://www.japanprobe.com/2010/07/29/japanese-kid-takes-solo...
My all time favorite unaccompanied traveller is my great grandmother, who emigrated to America with the address of family living in Chicago in her pocket. Being a young lass from the Irish hinterlands, she had no clue how to get there from NYC, and asked a passing Irishman how to do it. He called her a cab, and when the cabbie arrived asked for his license.
"Now James, this is how it is going to be. Young Miss May is going to visit her family, the Henries, out in Chicago. Here is money for the trip. After she gets there, she is going to write me a letter praising your character as a gentleman. If I do not receive that letter, James, I swear by all the saints that you are a dead man."
Obviously, since I am here to tell the tale, James was completed his task with dispatch.