The guy left nine in a spiral (5)
I believe the answer is:
helix
'a spiral' is the definition.
(I know that spiral can be written as helix)
'the guy left nine' is the wordplay.
'the guy' becomes 'he'.
'left' becomes 'l' (common abbreviation).
'nine' becomes 'IX' (roman numeral).
'he'+'l'+'ix'='HELIX'
'in' acts as a link.
(Other definitions for helix that I've seen before include "Three-dimensional object shaped like a corkscrew" , "Screwed coil" , "that goes round and round and up and down" , "'Spiral structure, DNA is a double one (5)'" , "Spiral shape" .)