Fuel pump wiring

On that car the relay should be the only source of power to the fuel pump. At the pump end there is a ground wire and the green power feed to the pump. The green wire goes up to a splice pack and from there to the relay. With the relay out the pump should shut off. There will be some residual pressure in the line but that shouldn't last over 30 seconds or so.
From the description there is something else powering the pump either through a shorted power feed or in the relay box. A quick way to tell would be to connect a test light to the red wire on pin 9 in the multipurpose connector under the dash to the right of the steering column. That isn't the data connector, it is the other test connection. The red wire also gets power from the fuel pump relay and is used to power the pump for testing. If a test light connected to it stays on or a voltmeter connected to it shows voltage if you remove the fuel pump relay then there is a short to power on that circuit. Does the car have anything aftermarket on it like an alarm or sound system that could have been connected to that wire?

The only way to find it will be through testing. You need to find the joint connector M34 on the left side of the dash. With it unplugged you can test for voltage on the pump side and the relay side of the wiring. That would narrow down which half of the wiring has the short. You don't really want to rewire because the short could cause other issues, not just the current problem. Say it is due to a wire getting hot or chaffing against another wire. That could cause the wiring to overheat and the car to catch on fire. Better to find the problem and repair it before that happens.

The short would be to another power feed, not to ground. That would cause the pump to run without the relay installed. If you have access to the pump, probe for power at the green wire with the key on. Then remove the pump relay. Do you still have any voltage at the pump? If so there is another circuit feeding it as removing the relay should shut the pump off.