score:6
$9000 is below the limit for declaration ($10,000) so you don't have to declare it, and it's legal to bring it into the country.
It is, however, a large amount of money. If you're stopped for some reason and it is discovered it is close enough to the declaration limit to be suspicious. If you have good documentary evidence that the money is yours and that you came by it by legal means then you should be OK, but that won't stop an over-zealous officer seizing it for further investigation.
If you can, use a bank to transfer the money.