Composer's offspring disheartened guests with German hotel (9)
I believe the answer is:
songsmith
'composer's' is the definition.
(I've seen this before)
'offspring disheartened guests with german hotel' is the wordplay.
'offspring' becomes 'son' (male offspring).
'disheartened' suggests removing the centre (the middle or heart is removed).
'with german' becomes 'mit' ('with' in German).
'hotel' becomes 'h' (phonetic alphabet).
'guests' with its middle taken out is 'gs'.
'son'+'gs'+'mit'+'h'='SONGSMITH'
(Other definitions for songsmith that I've seen before include "composer" , "Writer of popular numbers" .)