I wonder if you received a generic reply from your parish office simply because you are asking with a deadline over a month away? I know that on your end, time seems to be running out to get the sacrament at the current parish, but for most businesses and organizations like your parish, we simply don’t know what the world will look like next week, let alone in six weeks. The bishop might be trying not to take risks.
No one is saying don’t ask, but most folks here are just trying to set you up for the probable response (which is likely to wait until you get to the new parish). Keep in mind that exceptions in one parish might not be indicative that your parish will offer an exception. If yours is a diocese that is thinking of opening up mass to the public again now or in one or two weeks, the answer may be different than if your diocese is still in full lock-down. One parish may be able to spare someone to confirm your son. Another may only have one priest for everything and absolutely has to reserve their health so emergency sacraments can be preformed with lower risk (annointing of the sick and baptism are often preformed on very high risk individuals, so all who meet with them must be healthy).
Right now, we need to think in terms of Urgency, not just importance.
Your son’s confirmation is very important, but can wait.