At this point, there's nothing that can be done to these courts - nothing. Some places have tried to put six inches of blacktop down over the whole surface. You can do that, but every single crack will eventually come back.
In the '80s, the water would seep up through the cracks when it warmed up and the courts would be slick. Plus, they sloped the courts from the east to the west instead of putting a slight grade on each side so that it would slop either direction. That didn't help with the drainage.