Just read the whole thread. Agree with most of the comments that your iPad was not hacked. I do have a couple observations which may explain the events as you describe them, in order of likelihood:
1) Your Amazon account was hacked, but it was in no way related to your iPad, vacation, or Father's router.
2) Someone was playing with your iPad and inadvertently (or on purpose) made these Amazon purchases. This could have been done prior to you and your wife going to bed. IE - earlier that day or the day before (a child perhaps?)
3) The 9 web pages "opened" in Safari -> This is just a history, for the most part, showing the last 9 most recently opened websites. This is a "feature" of Safari. Doesn't mean they were all opened while you were sleeping.
4) Your wife made these purchases and/or was surfing on the iPad and inadvertently made these purchases.
Long shot possibility -> Someone got a hold of your iPad prior to your vacation. They surreptitiously installed Cydia and Veency on your iPad. Then waited for you to leave your house, followed you to your vacation spot, hacked the WEP secured router (only conceivable part of this plot), correctly guessed your IP address then VPN'd to your iPad. They then ordered these Amazon purchases, with plans to steal them from your porch once delivered.
What totally blows my mind is that you believe you might have been hacked, your iPad compromised and charges of around $4000 (was $8000 but amended in a later post) yet you don't want to wipe your iPad?
I would be very interested to know the conclusion to this story.
PS - as an experiment I set restrictions on my iPad, then successfully used VPN through Veency without needing to enter the password. So, the perp wouldn't have to know your 4 digit password, assuming they were successful in the other steps outlined above.