Calls in IT to organise trace (9)
I believe the answer is:
scintilla
'trace' is the definition.
(both can mean a small amount)
'calls in it to organise' is the wordplay.
'to organise' indicates anagramming the letters (I've seen 'organised' mean this).
'calls'+'in'+'it'='callsinit'
'callsinit' anagrammed gives 'SCINTILLA'.
(Other definitions for scintilla that I've seen before include "Minute spark" , "The smallest amount" , "scrap!" , "littlest bit" , "Tiniest bit" .)