People who are barred want to be amongst celebs of the second water (9)
I believe the answer is:
blacklist
'people who are barred' is the definition.
(individuals on a blacklist)
'want to be amongst celebs of the second water' is the wordplay.
'want' becomes 'lack' (synonyms).
'to be amongst' indicates putting letters inside (I've seen this in other clues).
'celebs of the second water' becomes 'B-list' (celebs below the A-list).
'lack' put within 'blist' is 'BLACKLIST'.
(Other definitions for blacklist that I've seen before include "Proscribe" , "(Put on a) roll of people considered untrustworthy" , "Boycott" , "Names of those banned, distrusted" .)