1. Grate 6 ears of corn on the large holes of a box grater into a bowl. Carefully slice off kernels from remaining 3 cobs using a sharp knife; transfer to bowl. Scrape cobs with back of the blade to extract creamy liquid into bowl.

2. Melt 1 tablespoon butter in a medium saucepan over medium heat. Cook garlic until fragrant, about 30 seconds. Stir in corn with liquid, thyme, and 1 1/4 teaspoons salt. Reduce heat to medium-low; cook, covered, stirring often, until corn is tender but still has a slight bite, 25 to 30 minutes. Stir in remaining 3 tablespoons butter until melted. Serve immediately.