Rising Democrat's rep used to bring in A-list celeb (9)
I believe the answer is:
superstar
'a-list celeb' is the definition.
'rising democrat's rep used to bring in' is the wordplay.
'rising' is a reversal indicator (going up in a down clue).
'to bring in' says the answer is hidden in the clue.
'ratsrepus' can be found hidden inside 'democrats rep used'.
'ratsrepus' reversed gives 'SUPERSTAR'.
(Other definitions for superstar that I've seen before include "Extremely famous performer" , "top celebrity" , "Dazzling genius" , "Very famous person" , "Celeb" .)