Very fast job, as the reformation (9)
I believe the answer is:
posthaste
'very fast' is the definition.
(posthaste means very quickly)
'job as the reformation' is the wordplay.
'job' becomes 'post' (post is a kind of job).
'reformation' indicates anagramming the letters.
'as'+'the'='asthe'
'asthe' anagrammed gives 'haste'.
'post'+'haste'='POSTHASTE'
(Other definitions for posthaste that I've seen before include "With particular speed" , "Speedily" , "Like Bat out of Hell" , "As quickly as possible" , "Yes!" .)