In 99% of cases you don't need a kernel driver.

I don't think anyone uses the "native" usb way on either windows or mac os, when it's so much easier to go through libusb.

I've personally done a custom DFU updater for Mac OS some time ago by using libusb. It worked just fine(tm). I don't want to try and evaluate how long it would have taken to do it with the mac api.