... short play, good in points and theatre's booming (8)
I believe the answer is:
plangent
'booming' is the definition.
(I've seen this before)
'short play good in points and theatre's' is the wordplay.
'short' means to remove the last letter.
'good in points' becomes 'nge' (I can't justify this - if you can you should give a lot more credence to this answer).
'and' is a charade indicator (letters next to each other).
'theatre' becomes 'NT' (National Theatre).
'play' with its final letter taken off is 'pla'.
'pla'+'nge'+'nt'='PLANGENT'
Can you help me to learn more?
(Other definitions for plangent that I've seen before include "Noisy" , "(Of sound) mournfully resonant" , "loud noise" , "Pathetic" , "booming" .)