Way back when the Super Ball first came out we tried every possible “experiment” with them. That was about 4 decades ago, and I don’t know whether they’ve changed the composition of the ball since then, but I do remember two things clearly:
No matter what we did, the best we could get was about 90% return on a bounce. That corresponds with ivn1188’s .92 coefficient.
It is entirely possible to shatter a Super Ball by hitting it hard enough with a baseball bat. It’s kinda cool actually, since the individual shards bounce when they hit the ground, but it does pose a limit to the Barry Bonds vs. 100 mph fastball experiment.