The restore by WiFi just means you can restore all your texts and settings over WiFi, before you had to use your mobile data to download it, which is a pain for us that aren't on unlimited internet plans as it can eat a lot.
I don't know how you've got 8%, I've got the 2 apps everyone says drains their battery whatsapp and Skype. I let everything run in the background, the only battery saving measures I've got is turning Bluetooth and NFC off. This morning I took the phone off charger and I didn't touch my phone for an hour when I looked at the battery app it said 0%, I've never seen it say 0 before.
The highest I've seen mine is 4% and that's if I'm streaming music on wifi or had the screen on a long time.