looking at a modern car 84-91 Astra Haynes pump is wired as follows.
12 to relay to fuse to the pump.
the control for the relay comes from ecu.
for an old car - no ecu - wire the control to switched ignition.
... but for additional safety, the control would be wired to alternator output with an override at ignition starter posiiton - that way the pump does not run when the alternator is not turning.
in addition a hidden switch (poor mans immobiliser) can be added to the circuit.