It's about vet in study again (9)
I believe the answer is:
reexamine
'study again' is the definition.
('examine' can be a synonym for 'study' so perhaps 'reexamine' is OK for 'study again')
'it's about vet' is the wordplay.
'it's about' becomes 're' ('re' means regarding or about).
'vet' becomes 'examine' (I've seen this before).
're'+'examine'='REEXAMINE'
'in' acts as a link.
(Other definitions for reexamine that I've seen before include "Check again" , "Vet again" .)