Sage Hiram has reformed one (9)
I believe the answer is:
maharishi
'sage' is the definition.
(I've seen this before)
'hiram has reformed one' is the wordplay.
'reformed' indicates an anagram.
'one' becomes 'I' (Roman numeral).
'hiram'+'has'='hiramhas'
'hiramhas' anagrammed gives 'maharish'.
'maharish'+'i'='MAHARISHI'
(Other definitions for maharishi that I've seen before include "Hindu spiritual leader" , "Religious leader" , "leading teacher" , "Spiritual teacher" , "Seasoned beef-pork sausage" .)