Daughter is to run at release (9)
I believe the answer is:
discharge
'release' is the definition.
(I know that release can be written as discharge)
'daughter is to run' is the wordplay.
'daughter' becomes 'd' (genealogical abbreviation).
'to run' becomes 'charge' ().
'd'+'is'+'charge'='DISCHARGE'
'at' is the link.
(Other definitions for discharge that I've seen before include "pay" , "Sack or fire weapon" , "cashier" , "Performance" , "empty" .)