Finally got around to repairing MP-09b. Regrettably there is even more damage than I first suspected. I was able to install the new knees and he is still able to be played with gently but his days of transforming are well behind him.
It's a real shame that such a nice toy is so fragile. I keep hoping for a black repaint of the MP-28 Hot Rodimus but we haven't seen anything yet.