The Collectible Item on level in Angry Birds Star Wars II Battle of Naboo level P3-9 is underwater below the slingshot. Burn Darth Maul and then send Zam Wessel down into the water. Attach his grappling hook onto the left side below the slingshot so that he circles back into the bonus box.
Go back to the Complete Star Wars II Bonus Boxes Guide. If you have a different strategy feel free to leave a comment below.
This was a little difficult – I certainly had to consult the video to get this one, but after that I had it within 10 attempts.