Warned education is failing (9)
I believe the answer is:
cautioned
'warned' is the definition.
(cautioning is a kind of warning)
'education is failing' is the wordplay.
'is failing' is an anagram indicator.
'education' is an anagram of 'CAUTIONED'.
(Other definitions for cautioned that I've seen before include "Warned by way of education" , "Education (anag)" , "Given formal warning" , "Gave warning" .)