As long as you have power going to both the main and 3PDT pcbs that’s ok and if, as you’ve said you get 9v readings on the pcb that confirms you’re getting power
When you say the potentiometers are not hooked up do you mean they are not soldered to the pcb? they need to be soldered to the pcb otherwise you’ll have an open circuit
Incidentally for a first kit that looks really good and very well put together I’m assuming you’re not new to electronics?