Got ex-pupil Edward to take adult in (8)
I believe the answer is:
obtained
'got' is the definition.
(obtaining is a kind of getting)
'ex-pupil edward to take adult in' is the wordplay.
'ex pupil' becomes 'ob' (abbreviation for 'Old Boy').
'edward' becomes 'ted'.
'to take' is an insertion indicator.
'adult' becomes 'a'.
'a'+'in'='ain'
'ted' placed around 'ain' is 'tained'.
'ob'+'tained'='OBTAINED'
(Other definitions for obtained that I've seen before include "Into a bed (anag.)" , "Got something" , "Got, procured" , "Acquired" , "Came into possession of" .)