I know I wont change your mind but I will give you my thoughts on the subject.
The old children become the more independence they want. As a parent you have to use your judgment to decide how much independence they can handle.
Making that judgment requires experimental testing on the parents part. The parent yields responsibility to the child and sees how they handle it.
Eventually you have to trust the child out of your sight. If you do not your child will rebel, become overly fearful of the world and/or become narcissistic.
Certainly there are great dangers in the world for a 9 year old. But you can not totally isolate him from the world. He must be taught to negotiate the dangers on his own. You will not be there all of the time.
I actually agree with a lot of what you’ve said except this: you don’t leave your child alone in a public place like Wal-Mart at the age of nine to see what they will do on their own. I guarantee they will behave childishly, you know, like a nine year old. Also, you don’t do it because there are too many perverts hanging out in public places waiting to snatch a kid.
By the way, I have an adult child, a teen and a ten year old. So its not like I don’t have a clue about what I’m talking about. And so far, no narcissists or rebelers at my house. And I pray to God it stays that way.