2005 Hyundai Tucson Short after fixing Starter

My 2005 Tucson recently wouldn’t start. I narrowed it down to a corroded connection at the starter solenoid. I trimmed the and extended the wire and and the initially tested the car by cranking it (with the ECU fused removed; suggested by the service manual). All was going well until I went to put the cover back over the starter when it began to spark. The car will no longer crank let and none of the the interior/dash or headlights work. The engine block of the car now yields a positive voltage of 9.0v volts. my battery is 12.6. I’m convinced something is shorting out i just don’t know where to begin. I’ve checked all fuses and fusible links and all are in tack. If anyone would have any suggestions on where to find the short I would be most grateful. I’ve started with the solenoid and power wires to the starter and all checks out. Please let me know if anyone has any ideas.

Thanks you all for your consideration.