Congregate around old, extremely deaf family bigwig (9)
I believe the answer is:
godfather
'family bigwig' is the definition.
'congregate around old extremely deaf' is the wordplay.
'congregate' becomes 'gather' ('gather' can be a synonym of 'congregate'**).
'around' is an insertion indicator.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'extremely' says to hollow out the word (remove centre letters).
'deaf' with its centre taken out is 'df'.
'o'+'df'='odf'
'gather' placed around 'odf' is 'GODFATHER'.
(Other definitions for godfather that I've seen before include "Mafia chief or spiritual parent" , "gang boss" , "Mafia boss" , "Mafia head" , "He sponsors a child at baptism" .)