If you have received your graduate letter of certificate already. you cannot work. because you status is implied status. If your study permit is not expire. you can apply PGWP, you can legally work.Please I know that a student with SP and SOWP applications (in process) can no longer work with expired study permit after completing his studies even if he has applied for extension of study permit but Can the spouse still work when he is on implied status or he also has to stop working when the student has finished his studies.