Place 2 cups oats in large bowl. Place plums in food processor or blender; process until blended. Add honey and vanilla; process to blend well. Add oat bran and remaining 1/2 cup of oats; process until well combined. Add puree mixture and orange juice to oats. Stir until well blended. Shape into 24 (about 1-1/4-inch diameter) balls (3 bites per serving). Refrigerate, covered, until chilled. Store leftovers in refrigerator, covered.