Uncertainty of Sun's leader writers in employ (8)
I believe the answer is:
Here is my best explanation:
'uncertainty' is the definition.
(suspense is a kind of uncertainty)
'sun's leader writers in employ' is the subsidiary indication.
'leader' indicates taking the first letters.
'writers' becomes 'pens'.
'in' means one lot of letters goes inside another.
'employ' becomes 'use' ('use' can be a synonym of 'employ'**).
The first letter of 'suns' is 's'.
'pens' going within 'use' is 'uspense'.
'of' is the link.
(Other definitions for suspense that I've seen before include "Anxious uncertainty", "Uncertain anticipation", "Uncertain state", "State of nervous uncertainly", "Hitchcock's speciality", "Apprehension, anticipation", "Excited uncertainty", "Nervous uncertainty; cessation", "State of anxious uncertainty while waiting (8)" and "State of nervous or excited tension or uncertainty".)