Notice that man hires followers (9)
I believe the answer is:
adherents
'followers' is the definition.
(adherent is a kind of follower)
'notice that man hires' is the wordplay.
'notice' becomes 'ad' (short for advert).
'that man' becomes 'he' (he refers to a man).
'hires' becomes 'rents' ('rent' can be a synonym of 'hire').
'ad'+'he'+'rents'='ADHERENTS'
(Other definitions for adherents that I've seen before include "'Supporters, disciples (9)'" , "Supporters of neatherds" , "Followers" , "Supporters of neat herds" .)