Measure vertical distance travelled
All an accelerometer will give you is time of flight.

while the ball is in the air it's in free-fall and the accelerometer will read zero.

if you can assume a level playing field you can calculate maximum height from time of flight.

for 10cm height time of flight will be about 200ms

throw in a 3 axis gyro, and you can estimate how hard it was thrown
and and how much of that throw was vertical, but time of flight is probably still your best bet.