What happens to my down payment, they accepted 9000$ plus trade in without car being financed.
They keep that.
Here's an example. Your figures may vary but you'll get the idea.
Let's say your purchase price was $30,000 including the extended warranty, tax, license, fees, etc.
You gave $9000 down and car worth, say, $5000 leaving a balance to be financed of $16,000.
You say the financing was declined when the car got wrecked.
Let's say the extended warranty cost $1000 and you get it cancelled and get a refund of $1000.
That means you owe the dealer $15,000. You either pay it now or the dealer takes the car back and sells it to a salvage yard. Maybe gets $2000 for the wreck.
Now you owe $13,000. If you don't pay it you get sued for it. The dealer gets a judgment, it goes on your credit report, the dealer can garnish your paycheck and levy your bank accounts and record the judgment so it becomes a lien on your home.
Now you can plug in your own figures to the equation and come up with a balance that you owe.
So far, you haven't answered the question as to who was at fault for the accident.