8 days is a long time to be gone during this delicate phase. You might just need to give them a good soaking right when you leave and then keep your fingers x'd.
Dont be surprised if their all keeled over when you get home.
I second this. Soak them, but allow for good drainage.. they may be in rough shape when you get back (dont worry)
When you are back, check to see how dry they are. If you can keep humidity up in your room and have your lights set up right, and soak them prior to leaving, you may have surprisingly good results.
Good luck to you and remember, if anything goes wrong you can always try again.