Possible Clues:

• High-street employee
• Graduate in son is that incompetent as retail worker
• Silly posh idiot first to oppress worker, one in sales
• Salesperson
• 'One's not on the job 9 down (4,9)'
• Post that's passion's undoing
• Worker in retail trade
• Give grass to aid one who's tilling?
• 1's acolyte seconds that passion, perhaps
• One in store dashed round to deliver embroidered satin