Yes, Tickets purchased as part of the LEGOLAND Vacations Hotel package can be used on any day during your stay. You don't need to be checked in to use your tickets for Park admission.
All your travel documents, including park tickets, will be emailed to you after 4pm (local time) 2 days prior to your scheduled arrival date. If you make a reservation within 48 hours of arrival, your tickets will be emailed to you within 24 hours.
For multi-day tickets, all visits must be used within 3 days of your first visit.