Moderate cider teen's drunk (9)
I believe the answer is:
intercede
'moderate' is the definition.
(thesaurus)
'cider teen's drunk' is the wordplay.
'drunk' indicates an anagram.
'cider'+'teen'='ciderteen'
'ciderteen' is an anagram of 'INTERCEDE'.
(Other definitions for intercede that I've seen before include "plead in prayer" , "Act between parties to reconcile differences" , "Plead for someone" , "Intervene, on behalf of another" , "Come between as mediator" .)