Work in bed? Initially, employer to play along (9)
I believe the answer is:
cooperate
'play along' is the definition.
(to cooperate is to work along with others)
'work in bed? initially employer' is the wordplay.
'work' becomes 'opera' (musical work).
'in' is an insertion indicator.
'bed?' becomes 'cot' (cot is a kind of bed).
'initially' indicates taking the first letters.
The initial letter of 'employer' is 'e'.
'opera' placed within 'cot' is 'cooperat'.
'cooperat'+'e'='COOPERATE'
'to' is the link.
(Other definitions for cooperate that I've seen before include "band together" , "Work constructively with others" , "Help" , "Play ball with" , "fit in with others" .)