I applied for my son's passport yesterday at Ottawa Passport Office located at 885 Meadowlands Drive East. I was told that the processing time is 10 business days and the passport is guaranteed to be delivered on or by June 4 (which is given me on a written receipt), via registered mail (exactly after two weeks). So in my opinion, do not change your oath date as it hard to get earlier date as well as it might delay your process. Even if you apply for normal processing time, you still have a week of buffer time. In the worst case, you can go with option of urgent processing (next day pickup), express pickup (2-9 business days) or standard pickup (10 business days) with some extra $$. Find detail here,
https://www.canada.ca/en/immigration-refugees-citizenship/services/canadian-passports/fees/passport-canada.html
Note: I was there during noon yesterday, which was the first work day of the week. It was not relatively crowded (around 50-70 people), but the entire process took me less than 30 mins. Waited 10 mins to receive token number, another 10 mins for my turn to submit application (there were ~15 applicant before me), and another ~10 mins to handover application and validate documents. They were pretty fast and efficient and have more than 10 kiosks to process our application.