Allow writer salary increase right away (9)
I believe the answer is:
authorise
'allow' is the definition.
(authorising is a kind of allowing)
'writer salary increase right away' is the wordplay.
'writer' becomes 'author' ('author' can be a synonym of 'writer'**).
'salary increase' becomes 'rise' (I've seen this before).
'right' becomes 'r' (common abbreviation).
'away' is a deletion indicator.
'rise' with 'r' removed is 'ise'.
'author'+'ise'='AUTHORISE'
(Other definitions for authorise that I've seen before include "OK" , "Give power to or sanction" , "Sanction, empower" , "I share out (anag.)" , "Sanction or establish officially" .)