Cryptic clues he'd put in the timetable (8)
I believe the answer is:
schedule
'the timetable' is the definition.
(thesaurus)
'cryptic clues he'd put in' is the wordplay.
'cryptic' indicates anagramming the letters (I've seen this in other clues).
'put in' is an insertion indicator.
'clues' is an anagram of 'scule'.
'scule' placed around 'hed' is 'SCHEDULE'.
(Other definitions for schedule that I've seen before include "Syllabus" , "Table of events" , "Agenda" , "Inventory - programme" , "Timetable for activities" .)