Car won't shut off...Help!

Could it be the coil?
No. It is getting power and as long as it does, the engine will run.

"Disconnect the + wire from the coil"
If you do this, DO NOT let the bare wire end touch any ground.
Why? Because it could ground the battery positive.
a. Obviously the wire is drawing power or the engine would not continue to run.
b. If it is in any way connected to the battery, touching ground will cause the battery to discharge as much current as it can .
With some luck the fusible link will fail before everything else melts.

Probably a safer way to shut off is removing the connector from the ballast resistor. The terminal on each side is in a connector and so less likely to ground. Still be careful.
Disconnecting either should shut the engine unless power is coming through the brown wire (normally ignition run when starting).

I beleive the '69 wiring is very similar to '68. So the ignition and charging circuits look as shown below.
Notice the wires that are always hot. The ones connected to the battery but don't go through the ignition switch. One of them may be touching the run circuit.

Charging-diagram68BV.png