Appear to enjoy drinking a double (9)
I believe the answer is:
lookalike
'double' is the definition.
(I've seen this before)
'appear to enjoy drinking a' is the wordplay.
'appear' becomes 'look' (synonyms).
'to enjoy' becomes 'like' (I've seen this before).
'drinking' is an insertion indicator.
'look'+'like'='looklike'
'looklike' going around 'a' is 'LOOKALIKE'.
(Other definitions for lookalike that I've seen before include "Double" , "twin?" , "Doppelganger" , "Copy" .)