You can't make any boots smaller or remove negative space. There's no brand or model that allows for this. You're right, the thermoformability of Trues makes them expand around your feet, plus you can get a good wrap, but it definitely doesn't allow them to shrink around your feet.
Beyond thermoformability, with Trues or any skate brand, you can punch or stretch them to make them wider, longer or deal with pressure points. Plus, padding compresses with use. That's why if you're between sizes, it's generally better to go with the smaller size. With Trues, it's ideal to have them feel too small and a bit too tight before baking and break in. If you feel room before baking, that's definitely not going to go away with baking - you'll only get more room after baking and break in.