I would leave them on a timer like I always do. Do you actually turn the lights on and off each day for them manually? For me the most difficult part of leaving home is the watering schedule and making sure temps and rh stay in bounds, the lights just do their thing. I would not leave them in the dark for 8 days, since they are autos you could leave the light on and dimmed some, that would be better than off. Timers are very cheap, I would invest in one.