Melt 1 Tbsp. butter. Drizzle over crackers in medium bowl. Add 1 tsp. seafood seasoning; mix lightly. Spread onto rimmed baking sheet sprayed with cooking spray. Bake 10 min. or until lightly browned.
Meanwhile, melt remaining butter in large saucepan. Add onions and celery; cook 5 min. or until crisp-tender, stirring frequently. Stir in sherry; cook and stir 30 sec. Add potatoes and chicken broth; stir. Bring to boil; simmer on medium-low heat 10 min. or until potatoes are tender, stirring occasionally. Remove 2 cups soup from saucepan. Blend in blender or food processor or until smooth. Return to saucepan.
Add clams, Worcestershire sauce and remaining seafood seasoning; stir. Simmer 10 min., stirring occasionally. Add cream cheese; cook and stir 2 to 3 min. or until melted.
Serve topped with seasoned oyster crackers.