He's got it completely wrong. It's the gyroscopic forces that control everything, which is why you can't balance when stopped or going very slow. He got close at 8:50, but he doesn't seem to understand how the leaning and steering are linked by the gyroscopic forces. When the bike rolls down the hill on its own, if it leans to one side, the steering goes the same way, so that the bike would go round in a circle, but the centrifugal gorce then acts to lean it the other way, so it goes straight. When you ride the bike, the counter steering envokes the gyroscopic force to lean the bike over, and you do the reverse to get it back upright. When the bike's leaning, you go round in a circle to balance your off-centre weight with the centrifugal force. You adjust the amount of lean by small adjustments of the bars left to go down and right to go up in a right turn.
Anyone, who's raced or ridden a motorcycle fast will know about counter steering. People thnk that you steer a motorbike by leaning, but if you let go of the bars and try to steer like that, you see that you can make small adjustments to your direction, but you can't turn a corner. Also, you get the picture very fast when you have your first go on a trike and it goes in the opposite direction to what you want.