Entertain a goddess, one of nine (5)
I believe the answer is:
amuse
'entertain' is the definition.
(amusing is a kind of entertaining)
'a goddess one of nine' is the wordplay.
'goddess one of nine' becomes 'muse' (one of the nine muses of classical myth).
'a'+'muse'='AMUSE'
(Other definitions for amuse that I've seen before include "Keep occupied" , "Cause to laugh or smile" , "interest" , "Enliven" , "Tickle" .)