There are several reasons why I should allow this without any penalties. And because it is early in the morning on a Saturday and I'm extremely bored, I'm gonna list all of them that I can think of
1. I am a strong supporter of what you may call stunt bonuses. The idea is from White Wolf's Exalted (as far as I know) and involves not only breaking the rules of the system but in fact also encouraging it by giving appropriate bonuses. I won't give you any specific bonus (except maybe XP), but I won't penalize you with unimportant rolls either.
2. A Force Power should be awesome, even if it is one that is as little descriptive as Battle Strike. A little spinning and a little jumping gives Battle Strike a much needed flavor.
3. A Jedi/Sith confrontation needs this sort of stunts. I want to encourage such activity.
4. Acrobatics would allow you to move over the box as if it weren't there, or move from a threatened space without risking an Attack of Opportunity. You're not trying to, though, so there's no reason to add such a roll to the mix.
And now for a reason why I should make you roll Acrobatics and ruin the whole flow of the action:
1. You did say he was jumping.
So you see, I have no actual reason to ruin the flow of the action in the scene, so I intend not to. You will move over the box as if it were 2 squares and Darth Cat will get an attack of opportunity. But you get to keep your action as is.
Additionally, I don't think you intended to stay on top of the box so I'd like to know (just for mapping purposes) where you intend Benjamin to 'land' or stop moving. Move two squares straight ahead (or further) or onto the box and one square down?