I agree with all. Elbows next to your ribs and connected to your knee when he attacks. Maintain your structural frame. If he can separate either of these during his attack your caught. When he dives,rolls, twists, etc, roll to your back(like you did) but deny him any control between your elbows and ribs or your back.
This is my main attack on buttscooters, because if you can beat him to the roll, you have positional advantage. Another option with this type of opponent would be to stand, clench, then pull guard. Easier to establish control on such an athelete. Im not sure if you drill dynamic guard pulling, but flying triangle or omo from standing overhook would fit beautifully in your game. Your good man.