Two Times Can't be a Coincidence...Dart not Firing
I tested coil to battery, normal readings. Tested ballast, normal. Swapped ballast, nothing. Tested wires on the plug to the ICU. Normal. Tested while cranking...got 9 volts out of 12. That was probably the only abnormal thing. .
What you wrote here, except for the 9v tells me exactly nothing. You need to detail "what" these tests are how you did them and what were the results
Where did you measure this 9V? At the coil? Is this using the key to crank the engine? To "finish" this test you need to do like so:
Measure at the coil cranking, using the key to engage the starter. Voltage?
Now move your meter to the BATTERY (or starter relay large battery post) and repeat the test. There should be just a few tenths of a volt different. That is, let's say the starter relay read 10 1/2--11V but your coil read 9V. That is a problem.
"When it quits" do some of the tests I detailed. Wiggle the ess ech eye tee out of the distributor connector. This connector has almost zero power going through it. It's a VERY low level signal, and if there's corrosion in there, it won't work. Working the connector "many times" in and out "scrubs" the terminals clean. I'd work it in/ out about 8-10 times.
Also you can put your meter on the distributor connections while disconnected, and crank the engine. With your meter set to low AC volts, the distributor pickup should generate about 1V AC
Inspect the distributor, wiggle the shaft for wear. Look carefully for rust and debri on and around the pickup, reluctor, magnet. Look for damage due to striking. Measure the resistance of the pickup. Should be 150-400 ohms or so. Should show infinity to ground.
Do the "tap" test I mentioned earlier. With power on, tap the engine harness side of the dist. connector to ground. The system should generate one "snap" spark each time.
"If you feel you must" put points back in you can EASILY do that with very little effort. Simply unplug the ECU connector, and disconnect the coil NEG terminal. Install the points dist, and hook the dist. wire back up to coil NEG and re-time.