Presiding officer (9)
I believe the answer is:
moderator
'presiding officer' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for moderator that I've seen before include "One checking discussions conducted fairly" , "clerical figure" , "Presbyterian minister - superintendent of university examinations" , "Site foreman" , "Someone who presides over a forum or debate" .)