A pact goes to pieces - blame him (9)
I believe the answer is:
scapegoat
'blame him' is the definition.
'scapegoat' can be an answer for 'blame'. I am not sure about the 'him' bit.
'a pact goes to pieces' is the wordplay.
'to pieces' is an anagram indicator (the same pieces in a new order).
'a'+'pact'+'goes'='apactgoes'
'apactgoes' with letters rearranged gives 'SCAPEGOAT'.
Can you help me to learn more?
(Other definitions for scapegoat that I've seen before include "One is punished for the errors of others" , "Whipping boy" , "I'll take the blame" , "Patsy" , "Person blamed for the wrongdoings or mistakes of others" .)