The first thing I tried was moving to the frame where the vanilla ball bounce hits the ground and in that key frame I moved the top handle of the ball up and the bottom handle of the ball down. I assumed it would gradually move into this stretched position as the ball fell to the ground. Instead, when I moved back to the first key frame where the ball is in the air, it was in the exact same stretched position as it was on the ground. Next I tried selecting the top and bottom handles of the ball and giving them their own key frames. I tried the location key frame and then repeated the steps from the first sentence of this paragraph but had the same issue. I then tried the exact same thing but with the scaling key frame and again had the same issue. I have no problem getting the ball to squash and stretch but I just can't seem to figure out how to get it to change the amount of squashing/stretching from one frame to another.
I figured out the problem. I had deleted all the other axis in the key frame except Z since the handles were only going up and down. I am not sure why but after some trial and error I found out that the Y axis is what allows them to move up and down on the Z axis in this case.
