I can only speak for the tables that I've run at the local store, but no one will be 3rd level going into tomorrow's session. You would only be 3rd level now if you had attended all nine of the previous sessions. There are two people who've attended eight of nine, so they should level up after tomorrow. There are new level 1 characters every week, and that's fine - I scale the encounters appropriately based on the strength of the table.