Holy room service - it's scary (8)
I believe the answer is:
sacristy
'holy room' is the definition.
'sacristy' can be an answer for 'room' (sacristy is a kind of room). I am not certain of the 'holy' bit.
'service it's scary' is the wordplay.
'service' indicates anagramming the letters (I've seen 'serviced' mean this (to service can mean to repair)).
'its'+'scary'='itsscary'
'itsscary' is an anagram of 'SACRISTY'.
Can you help me to learn more?
(Other definitions for sacristy that I've seen before include "Church's sacred vessels store" , "Satyr (sic) found in church storage room" , "Vestry" , "Part of church" , "Room in church for vestments etc." .)