Combine first 4 ingredients in a bowl; stir well.
Let stand 15 minutes.
Remove fruit from bowl, reserving syrup.
Thread pineapple cubes and plum wedges alternately onto 2 (6-inch) skewers.
Place kebabs on grill rack coated with cooking spray; grill 4 minutes on each side or until thoroughly heated.
Drizzle reserved syrup over kebabs; sprinkle with cookie crumbs.