If you stay onsite, you can enter at 9am through the GCH entrance. If you stay offsite you can enter at 9:30am. 9:30 is the unnofficial opening of DCA, though the whole park won't be open. Soarin will, WoC Show Pass distribution will, and Little Mermaid will be open a little later for non hotel guest, open for hotel guest at 9am. Also rope drops will be set up, mostly for TSM.