There should be two dates on your contract; Closing and Possession. Closing is when the deed legally records the property in your name. Possession is when you get keys and have full access. As Kary noted, you should be entitled to the keys no later than 9:00 pm on the possession date. Congratulations on your purchase.
As others have noted, it depends on what your contract says. Assuming day of closing and the standard statewide form, you're entitled to the keys at 9:00 p.m. on the closing date. If the property is vacant you can probably get the keys as soon as the deed records with the approval of the seller's agent.
It depends on which box is checked on page 1, line 12 of your purchase and sale agreement. If the box next to (on closing) is checked off then you should get the keys on the 9th once everything has been recorded with King County. If the box next to (other) is checked off then it could be a different day than the 9th. I would call your agent and ask them how they planned on getting you the keys and when.
Agreeing with Shanna Rogers, if your purchase and sale says possession on closing, it should be that day. The caveat might be if the closing is late enough in the day that the deed is not recorded until the following day, the key may not be released till then.
If the purchase and sale says something like "3 days after closing," don't pack your bags quite yet.