Looks very cool.
I have no idea what your DD's challenges are so please disregard if this doesn't help - have you tried a balance/run bike? At that age the easiest/cheapest thing would be to take the pedals and cranks off a regular bike (no training wheels). The kids then sit on the bike and walk eventually building up to pushing off and coasting (think running but with some sitting on a bike and coasting between strides).
It won't solve the pedaling issue but it might give her something to tool around the neighborhood with and possibly keep up with siblings or other kids who are on bikes. My kids had them and I had to jog to keep up with them as toddlers. They do help with balance which eventually will be useful once she sorts the pedaling out. We also liked that they handled off roading and gravel better bikes with training wheels.
Again, no idea if that is a possibility for your situation. If you want google "strider bikes you tube" and there are lots of videos (most of the kids are young so I wouldn't show them to a 9 year old) but it will give an idea.
