Preheat oven to 400°F. Line a baking sheet with foil and coat with spray oil.
While wearing gloves, slice jalapenos lengthwise in half. You can remove stems, if you desire. Using a spoon, scrape out seeds and ribs. Arrange peppers, on baking sheet.
In a medium bowl, mix the softened cream cheese, cheddar cheese, salt, pepper, and onion powder, if using. Mix well.
Fill each jalapeno half with cream cheese mixture and return to baking sheet.
Cut bacon in half, crosswise. Carefully wrap bacon slices around each pepper. Secure with toothpicks, if desired.
Bake for 20-25 minutes at 400° F or until bacon is browned and crispy. Serve immediately.