Person punished positioned to welcome better self (9)
I believe the answer is:
scapegoat
'person punished' is the definition.
'positioned to welcome better self' is the wordplay.
'positioned' becomes 'sat' (sitting is a kind of positioning).
'to welcome' indicates putting letters inside (in sense of 'inviting in').
'better' becomes 'cap' (I've seen this before).
'self' becomes 'ego' (synonyms).
'cap'+'ego'='capego'
'sat' going around 'capego' is 'SCAPEGOAT'.
(Other definitions for scapegoat that I've seen before include "Patsy" , "One who takes the blame for others" , "Aunt Sally" , "One made to take blame" , "One blamed for others' mistakes" .)