Can you post your setup? Is the turbo internally gated? If it has an internal gate and you disconnect the actuator arm to the flapper, you shouldnt be able to build more then 1-2psi of boost. If you do a boost leak and it starts leaking at 9psi, there is your first problem. What BOV do you have? Even a stock 1g bov will be able to hold 22-25psi stock before it leaks. You should be able to pressurize the charge pipes to 5,10,15,20psi(whatever you want) and it should hold that pressure if you shut the valve off on the air compressor.

Something doesnt sound right about your setup. Can you make up a quick diagram in MSPAINT of the vacuum lines?