In an Instant Pot, toss butternut squash, carrots, garlic, onion, celery, and 1/2 tsp each salt and pepper. Tie thyme and sage sprigs into a small bundle with twine, then place on top of vegetable mixture. Add broth and lock lid. Cook on [Manual High Pressure] for 20 minutes. Natural release for 15 minutes then release any remaining pressure. Let cool slightly then discard herb bundle. Using an immersion blender (or standard blender, in batches) puree soup. Meanwhile, heat oil in small saucepan on medium. Add sage leaves and cook stirring occasionally, until bubbles subside. With slotted spoon, transfer leaves to paper-towel-lined plate to drain. Serve soup drizzled with oil and topped with crispy sage.