He's done something shameful about verification of the will (9)
I believe the answer is:
reprobate
'he's done something shameful about verification of the will' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he's done something shameful about verification of' is the wordplay.
I cannot quite see how this works, but
'about' could be 're' ('re' means regarding or about) and 're' is located in the answer.
'of' could be 'o' and 'o' is found within the answer.
'he' could be 'bat' and 'bat' is found within the answer.
The remaining letters 'pre' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for reprobate that I've seen before include "17 [WRONGDOER]" , "scoundrel" , "Berate pro, being an unprincipled person" , "One who lacks principles" , "Disapprove of" .)