score:3
I wouldn't worry about it. While carry-on item sizes can be enforced pretty strictly, nobody pays attention to personal items unless you're clearly going above the limits. But if you want to play it 100% safe, just leave enough space in your carry-on to stuff the laptop if you need to.
For what it's worth, I usually travel with a carry-on rollaboard bag and a backpack, which is larger than 9"x10"x17", and have never been hassled about it.