The issue's with adding to your existing floor are many.
The exterior doors and thresholds will need to be lifted up to clear any wood you put down, The doors will not open in. Any stairs will need to be raised to meet code. The doors on the interior will need to be all cut down and baseboard all redone. If you have baseboard floor heat it will need to be adjusted up also.
And the floor will still have bounce when you are finished.
All this is a lot more work and money than what is needed in the crawlspace.
Buy a nail gun and compressor and take your time. Get a pair of overalls and a good dust respirator.
This is hard work and I know it is not easy, but you will be much more satisfied when you are finished for doing it the right way.