On non-EMH mornings, they'll open the touchpoints for Breakfast Guests and Star Wars Guided Tour Guests only around 8am. Around 8:30 is when they'll open for everyone else, but still hold them at the end of the Trolley Car Cafe. Then it depends on the attractions status and how busy Hollywood Blvd. is becoming. (For instance they won't open early if RnRC isn't open yet, they usually wait until everything is ready.) I've seen them open at 8:45, up to 9:00, and everything in between.
EDIT: Today they opened at 8:40, probably because of the rain (not having guests get rained on while waiting on Hollywood Blvd.)