DCA opens at 9:30 for all guests, not just resort guests. Only a portion of the park will be open and only Soarin will be open for that first 30 minutes until official park opening at 10 am.
However, a little known perk for GCH guests that is not advertised, is that if you get to the resort entrance of DCA right around 9 am, and tell the CM you want the Condor Flats Tour, a CM will come and take you on a little tour of Condor Flats area prior to the 9:30 opening. You will also be the very first group on Soarin and be guaranteed front row center seats.
I did this in June 2005 with my daughter, and I believe they are still offering this to GCH guests. Just ask at the GCH turnstiles into DCA.