Sort of preacher to want more liars converted (9)
I believe the answer is:
moraliser
'sort of preacher' is the definition.
(someone preaching about morals)
'more liars converted' is the wordplay.
'converted' indicates anagramming the letters.
'more'+'liars'='moreliars'
'moreliars' anagrammed gives 'MORALISER'.
'to want' acts as a link.
(Other definitions for moraliser that I've seen before include "preacher" , "Ethical speaker" .)