I think the hardest part of driving is learning the psychology of other road users and understanding both the positive and negative consequences of your actions. This requires experience and practice.
Based on the police footage, he wasn't doing a very good job of maintaining his lane, but he apparently managed to avoid hitting any stationary objects, so... go figure?
https://en.wikipedia.org/wiki/Lewis_Hamilton#1993%E2%80%9320...
Driving lessons pretty much assume an adult can control a car, they're mostly about how to safely and legally drive on shared public roads, and that's where I'd expect an 8 year old to be significantly less capable, without evidence to support it except - if 8 year olds were as capable of dealing with situations as adults are, we'd call them adults.
Trained? Don't think so. I mean, there are dogs riding skateboards, so I believe that, given the proper ergonomic controls, they could learn how to drive a vehicle.
Driving a vehicle safely (as in, not stopping in the middle of a highway to investigate an interesting object) would be a greater challenge.
But as far as navigating a space? Sure, they are amazing at that and far better than anything we can come up with in the near future. Heck, if you hook up an insect brain inputs and outputs, you would have a system that's better than what we currently use.