Butternut squash is made mostly of water, as are all fruits, so it will not crisp.
And why do you want to crisp up such a lovely fruit, that is meant to be eaten soft or as a soup.
Agree with the other two but best I can suggest is if you oven-roast it on an open tray and use an oil-spray to give a thin film on it and see if that helps.
This works with all sorts of root vegetables but, as mentioned, you're trying to crisp a very "wet" vegetable there!