Things to observe after resorting to an alibi (9)
I believe the answer is:
notabilia
'things to observe' is the definition.
(notable things)
'resorting to an alibi' is the wordplay.
'resorting' is an anagram indicator.
'to'+'an'+'alibi'='toanalibi'
'toanalibi' with letters rearranged gives 'NOTABILIA'.
'after' is the link.
(Other definitions for notabilia that I've seen before include "Remarkable things" , "Things worthy of attention" , "Noteworthy sayings" , "objects worth attention" .)