Accompanying a model mind worker (9)
I believe the answer is:
attendant
'accompanying' is the definition.
(I know that accompanying can be written as attendant)
'a model mind worker' is the wordplay.
'model' becomes 't' (Ford Model T car).
'mind' becomes 'tend' (to tend is to look after or mind somebody).
'worker' becomes 'ant' (worker is a type of ant).
'a'+'t'+'tend'+'ant'='ATTENDANT'
(Other definitions for attendant that I've seen before include "escort" , "waiter" , "Accompanying - custodian" , "One present to guide, help" , "Related" .)