Agreeing with you entering credit study (8)
I believe the answer is:
consider
'study' is the definition.
(I know that study can be written as consider)
'agreeing with you entering credit' is the wordplay.
'agreeing with you' becomes 'on side' (as in keeping someone on side).
'entering' means one lot of letters goes inside another.
'credit' becomes 'cr' (abbreviation).
'onside' going into 'cr' is 'CONSIDER'.
(Other definitions for consider that I've seen before include "Think about, reflect upon" , "Ponder on" , "Think carefully about" , "Contemplate" , "Deem to be, regard" .)