Instrument made of tin a butcher held up (5,4)
I believe the answer is:
snare drum
'instrument' is the definition.
(snare drum is a kind of instrument)
'tin a butcher held up' is the wordplay.
'tin' becomes 'Sn' (Sn is the chemical symbol for tin).
'butcher' becomes 'murder' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'held up' says the letters should be written in reverse.
'murder' back-to-front is 'redrum'.
'sn'+'a'+'redrum'='SNARE-DRUM'
'made of' is the link.
Can you help me to learn more?
(Other definitions for snare drum that I've seen before include "one's beaten" , "instrument for beating" , "nine [RUFF] could come from this" , "item in kitchen?" , "One may produce a rattling sound" .)