Crowd get up where musicians play (9)
I believe the answer is:
bandstand
'where musicians play' is the definition.
(platform for a band to perform on)
'crowd get up' is the wordplay.
'crowd' becomes 'band' (both can mean a group of people).
'get up' becomes 'stand' (to stand up from a sitting position).
'band'+'stand'='BANDSTAND'
(Other definitions for bandstand that I've seen before include "Outdoor music platform" , "place to play?" , "park feature?" , "Outdoor concert stage" , "Park structure for musicians" .)