You have to throw a little more than a slight hook, not a lot of hook.
Actually, once you start thinking of it as harder or different from the 3/6/9/10, you've already missed it. Think of it as having to hit slightly more of the 3 pin than when you make the 3/10. Because of that you should not stand quite as far left (assuming you're right handed) as when you throw at the 3/10. You have to hit the 3 pin on the right and have the ball deflect slightly into the 9/10.
Normally when you throw at the 3/10, you want to hit as little of the 3 pin as possible, and you can throw a small hook or a straight ball. You can't throw a straight ball at the 3/9/10 or the 3/6/9/10 unless you want to depend on luck or sheer ball speed.