Runner in confusion, turning green (9)
I believe the answer is:
messenger
'runner' is the definition.
(I've seen this before)
'confusion turning green' is the wordplay.
'confusion' becomes 'mess' (mess can mean confusion or chaos).
'turning' indicates an anagram.
'green' is an anagram of 'enger'.
'mess'+'enger'='MESSENGER'
'in' acts as a link.
(Other definitions for messenger that I've seen before include "Runner" , "One who bears a communication" , "Communication carrier" , "The role of Hermes or Mercury?" , "He takes note" .)