Get a new one. You don't know which damage is done except for the voltage regulator. So fix that and you probably will find out that the 328P and the TTL-to-USB did not survive the 9V.
Get a new one. You don't know which damage is done except for the voltage regulator. So fix that and you probably will find out that the 328P and the TTL-to-USB did not survive the 9V.