Combine the cherries, vinegar, mustard, fennel seed, salt and garlic in a blender. Puree until smooth. Place the chicken pieces in a resealable plastic bag and pour the marinade over the chicken. Seal the bag and toss to coat. Marinate in the refrigerator for 2 hours.
Remove the chicken from the refrigerator 30 minutes before grilling. Preheat a grill to 450 degrees F or medium-high heat with indirect heat on one side.
Remove the chicken pieces from the marinade and place on a baking sheet; reserve the marinade. Drizzle with the olive oil. Place the chicken on the grill over direct heat and cook undisturbed for 4 minutes. Flip the chicken, move to indirect heat and baste with the marinade. Cover the grill and roast until the chicken is cooked through, about 30 minutes. Remove to a platter and sprinkle with the fennel pollen.