Well you are right and wrong. You are right that Bob is correct and Jill is wrong, but the reasons behind it are different. (And yea I did word it very strangely. The seeing it in slow motion was just for reference but actually that would be impossible as you said). As you know, Gravity has an effect on time, and the higher the gravity on something the faster time seems to move for it. In order to reach that near speed of light, Jill would have to accelerate and acceleration creates a sort of artificial gravity (think taking off in a plane). Now apparently artificial gravity is actual gravity in some meaning of the word and effects time as gravity would. So the acceleration and deceleration needed to reach the speed and get down from it are mathematically (not gonna write it out) just enough to counteract the effects of her speed (or Bob's speed when you look at it like that) so to her 8 years passes, and to Bob that acceleration and deceleration made him older than 8 years by the time the predicament was over. Ta da!