Add olive oil to large heavy-bottomed pot and heat over medium heat. Add onions and sauté until translucent and the edges begin to brown, about 4-5 minutes. Add garlic and fennel seeds and sauté until fragrant, about 1 minute.
Stir in white wine and cook until the wine is reduced by half, about 2-3 minutes.
Stir in broth, water, Worcestershire sauce, bay leaf, and oregano and increase heat to medium-high. Bring mixture or a boil and then reduce heat to low.
Add meatballs and pasta and cook for 10 minutes, or until pasta is tender and meatballs are cooked through.
Stir in kale and cook for 1 minute. Finally, season the soup with salt and pepper and serve with grated Parmesan.