Working with "problematic" kids I came to a few conclusions, all of which I obviously can't know to be correct, but still. The first and foremost was approximately this: One should almost never assume what children can, and can't do. The individual differences seem to be wider than the oceans, and the only way to really know is to teach, trust, and fearless observation.
Most kids will know if you don't trust them, I've seen some 6 years old be "mortally" afraid on an adventure course for kids, as long as their parents were in view. When they could no longer see their parents, their courage grew by the second, and they did their small zipline with the proudest smile one can imagine.
It's quite scary, as a parent, to observe the power we wield. That our fears can directly create fear in our children, even if we try to hide them. These parents were supportive and encouraging, but they had their own fears, fears which they couldn't hide well enough, and the kids knew instantly, and instinctively.
Most parents grant them that autonomy you're talking about way, WAY too slowly. Would you let a 5 year old walk a couple of blocks down to the corner store to buy milk alone? If your answer is no, you're on the "too slow" side of the spectrum in my opinion.
It's pretty easy to gradually ramp up to this and to continue ramping up to more indepdendence at a much faster pace than most parents do.
No no no.
My 10 year old child definitely should not have adult-level autonomy.
It is my responsibility as a good parent to train my child by limiting aspects of their life. My children do not have unsupervised access to the internet. They do not have unlimited screen time. They cannot go on social networks and make friends with random people.
It is my job as a parent to not abuse my position as a parent. But I would fail my children greatly if I gave them autonomy over many aspects of their life.
As they prove themselves adept at self-regulation, growing wisdom and good judgement then, and only then, do I grant them more autonomy.