They make electrical contact cleaner, kind of like dry cleaning solvent. You could unhook any connections underdash, under the hood, etc and spray them, or at least hit them with some low pressure air to dry them. Remove the seats and carpet, clean them and reinstall them after making sure the metal is all dried out underneath (and/or coated in POR 15 as suggested). Car is DEFINITELY salvageable, just takes some time. I had someone break a window in a car during the rain, flooded the interior. I put a dehumidifier IN the car and ran it while I was nearby. Then removed the seats and carpet and used a steam cleaner while they were out of the car to get everything.
with salt theres no winning
ive dealt with a few from right after water receded
after a hose out and a drain and refill of fluids it might run , but that feeling of victory wont last
within days
harness connections will crumble , no cleaner or corrosion inhibitor will help , it deteriorates connectors rapidly
the harnesses are junk and theres more than just the dash harness and engine harness
fabric interior/carpet is junk , that saltwater stink can make you sick and the frame wires will crumble
dash radio controls all junk
the plastic can be washed
as for metal body , if the car was in salt water for any time the metal will corrode ,
being its day 9 id say it junk and will be rusting away in a few weeks
best chance on body would be if it had been adressed quickly (within an hour salt acts fast and is mean)
strip out the interior and all the floor matting and heavy matting
flush the car with fresh water (like drive it into a fresh water pond)
soak with corrosion imhibitor like WD that can seek out the cracksand displaces moisture
, dont seal it it needs to dry completely
the motor needs dissasembly , wash and reassebly , anything corroded goes to trash
you could drain and fill and redrain and fill and hope but the rest of the car will be apart so might as well just pull it apart redo and make sure its right
starter will be junk as will alternator ,cooling fan , blower and wiper motor
trans needs dissembly, clean and a rebuild with new clutches , anything corroded that is a contact surface goes to trash
rear needs to be disassembled all bearings washed and checked (replaced) , housing flushed and reassembled
pretty sure i was asked about this car a few days ago..its a shame
oh and it wasnt insured so i was told and besides it says so in OP