Buyer turned up with right drink (9)
I believe the answer is:
purchaser
'buyer' is the definition.
(synonyms)
'turned up with right drink' is the wordplay.
'turned' says the letters should be written backwards.
'with' says to put letters next to each other.
'right' becomes 'r' (common abbreviation).
'drink' becomes 'chaser' (I've seen this before).
'up' backwards is 'pu'.
'pu'+'r'+'chaser'='PURCHASER'
(Other definitions for purchaser that I've seen before include "I'll buy" , "he's bought" , "Buyer" , "Punter" , "customer" .)