Heat oil in a large Dutch oven over medium-high heat. Add fennel and onion, and sauté for 5 minutes. Add zucchini and the next 10 ingredients (zucchini through garlic); bring to a boil. Cover, reduce heat, and simmer 30 minutes. Add peas, parsley, basil, and clams, and cook, uncovered, 5 minutes. Ladle soup into each of 8 bowls; sprinkle with cheese.