If your Good soil comes next Friday, grab a small bag of potting soil from any location. I'd avoid ones with "nutrient boosts" and the like. You basically are looking for the most mellow so they can get through until the desired stuff arrives. Do get something that has perlite in it to help avoid soil compaction and improve air in the root zone. Don't get anything with big bark chips in it.
Before you put your plugs in it, do be sure to wet the new soil and do a test on the run-off water. I'd assume the soil is in the desired PH range, but assuming can lead to bad things when you are buying a cannabis specific product. I'd also use it in a small amount, like a solo cup size. It doesn't have long to go until it will be transplanted again.