Sprinkle scallops on both sides with salt and pepper. Heat oil in a large nonstick skillet over medium-high heat. Reduce heat to medium and add the scallops; cook, turning once, until browned on both sides, about 6 minutes total. Transfer to a plate.
Cook spaghetti squash in an oven @ 450 degrees until mushy. Scoop pulp out when cool enough to handle.
Whisk wine and clam juice in a small bowl until smooth.
Cook garlic in the pan over medium-high heat, stirring often, until softened, 1 to 2 minutes. Add the wine mixture; bring to a boil and cook until thickened, about 2 minutes. Stir in lemon juice, capers stir, 1 to 2 minutes.
Return the scallops to the pan, add the spaghetti squash and cook, stirring gently, until heated through and coated with the sauce, about 1 minute. Stir in parsley and serve immediately.