Excel scan modified in course (9)
I believe the answer is:
transcend
'excel' is the definition.
(transcending is a kind of excelling)
'scan modified in course' is the wordplay.
'modified' is an anagram indicator.
'in' means one lot of letters goes inside another.
'course' becomes 'trend' ('trend' can be a synonym of 'course'**).
'scan' anagrammed gives 'ansc'.
'ansc' put into 'trend' is 'TRANSCEND'.
(Other definitions for transcend that I've seen before include "Surpass (an achievement)" , "exceed?" , "Go beyond, surpass" .)