Racists converted by an official in church (9)
I believe the answer is:
sacristan
'official in church' is the definition.
(type of church official)
'racists converted by an' is the wordplay.
'converted' indicates an anagram.
'by' says to put letters next to each other.
'racists' anagrammed gives 'sacrist'.
'sacrist'+'an'='SACRISTAN'
(Other definitions for sacristan that I've seen before include "Church official" , "Church officer in charge of sacred objects" , "Church officer in charge of sacred vessels etc" , "Sexton" , "Church worker" .)