Heat a large pot of salted water to a boil and cook pasta according to directions. Drain and rinse under cold water to halt cooking. Reserve ¼ cup pasta water for the sauce.
Chop zucchini into quarters lengthwise, then into ½ inch slices - no need to peel. Heat olive oil in a large pan over medium-high heat. When oil is hot, add chopped zucchini, garlic, and thyme. Let cook until zucchini is soft and golden, around 10 minutes. Add salt and pepper to taste. Mash ¾ of the zucchini in the pan using a potato masher or wooden spoon until the mixture becomes saucy.
While zucchini is cooking, sear the scallops. Make sure that scallops are thoroughly dried to ensure a sear. Salt scallops and heat oil in a cast iron skillet (or nonstick) over high heat. Once the pan is hot, add scallops in an even layer (cook in batches if necessary). Sear for about 1 minute on each side, depending on the size of your scallops. Remove to a plate.
Add reserved pasta water to zucchini and bring mixture to a boil. Add in butter and parmesan and cook until melted, around 2 minutes. Lastly, turn off the heat and add in pasta and chopped basil, mix to coat the pasta in sauce. Divide onto plates and top with seared scallops. Serve with parmesan and fresh basil.