An instrument at home to open red wine? (8)
I believe the answer is:
clarinet
'an instrument' is the definition.
(clarinet is a kind of instrument)
'home to open red wine?' is the wordplay.
'home' becomes 'in' ('he's home' can mean 'he's in').
'to open' means one lot of letters goes inside another (some letters create an opening in a word).
'red wine?' becomes 'claret' (claret is a kind of red wine).
'in' put into 'claret' is 'CLARINET'.
'at' is the link.
(Other definitions for clarinet that I've seen before include "Single-reed straight-tubed instrument" , "Woodwind instrument played by Artie Shaw and Benny Goodman" , "Wind instrument made from Clare tin" , "Source of music" , "Woodwind instrument - Artie Shaw played one" .)