Hit a ball right up. Heavens! (3)
I believe the answer is:
sky
'heavens' is the definition.
(sky is a kind of heavens)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for sky that I've seen before include "Firmament" , "Hit (a ball) very high" , "Outer space viewed from earth" , "Hit high into the air" , "Strike up" .)