Scriptures keeping theologian, American, easily persuaded (8)
I believe the answer is:
biddable
'easily persuaded' is the definition.
(I've seen this before)
'scriptures keeping theologian american' is the wordplay.
'scriptures' becomes 'bible' (I've seen this before).
'keeping' is an insertion indicator.
'theologian' becomes 'dd' (Doctor of Divinity degree).
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'dd'+'a'='dda'
'bible' enclosing 'dda' is 'BIDDABLE'.
(Other definitions for biddable that I've seen before include "Easily controlled" , "Ready to be instructed" , "Obedient" , "Willing to be instructed" , "Willing to obey" .)