[VetteVet]

This probably is related to your other thread about the voltmeter and may be the cause for the 9 volt reading you are seeing. Take voltage readings as I suggested in that thread and compare them. If you're seeing fluctuating readings compared with the flashing charge light, I would say that you are having charging problems and they are most likely caused by the wiring to the alternator.
You should have a CS style alternator and it has two wires in the plug into the alternator.
One will go to the S terminal and one will go to the L terminal. The S terminal wire should be large gauge than the L terminal wire. It is the sensing voltage wire and it should be connected to a battery junction wire with the alternator charging wire.
The L terminal wire is a smaller gauge wire and will come from the key on, ignition circuit. If it has poor connections or broken strands it will cause the charge light to flash.
The alternator may also be the cause of the light flashing if it has a bad voltage regulator or diode inside.