Figures to reform most sinners (5)
I believe the answer is:
nines
'figures' is the definition.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for nines that I've seen before include "In emergency, press three of these" , "9s" , "squares" , "Numbers to which one may be dressed up?" , "Dressed to these is to be perfectly turned out" .)