Support senior team's leads and get on behind the scenes (9)
I believe the answer is:
backstage
'behind the scenes' is the definition.
(I've seen this before)
'support senior team's leads and get on' is the wordplay.
'support' becomes 'back' (to back is to support or endorse).
'leads' indicates taking the first letters.
'and' says to put letters next to each other.
'get on' becomes 'age' (getting on means aging).
The first letters of 'senior teams' is 'st'.
'back'+'st'+'age'='BACKSTAGE'
(Other definitions for backstage that I've seen before include "dressing room area" , "out of the limelight" , "Wings etc" , "Behind the scenes (theatrically)" , "away from public view" .)