There definitely
is a Bluetooth driver that works in 9x. I had one driver package from a BT dongle installation mini-CD, then I found (maybe mentioned here in these forums?) two other rather huge packages (35MB and 62MB, respectively) that were distributed by D-Link and Emtec. All of these packages contain an inf with a long list of vendor and product IDs and software produced by Widcomm.
But there's a catch: while the driver (namely
btcusb.sys - do not mistake with
btwusb.sys which does not work in 9x!) does work in 9x, the software - depending on version and package it's been installed from - may throw an "Evaluation mode" notice and limit transfer to 5MB!!! I wouldn't risk being banned by posting my blunt opinion about this practice but you get the idea.
Thing is, the driver is useless without a working application for it, so this should be our main concern: finding a proper application that'd work with the respective driver and all supported devices. All of those packages bundle the BlueSoleil application by IVT, but not all versions work in 9x. I did find one that does, with the above-mentioned limitation.
There's more to dig in related to this, maybe parts of the packages can be put together for a more complete set of options.
On another note, I just stumbled into another interesting matter:
Windows Easy Transfer. It's (among other functions) a driver for a special cable that allows USB-to-USB direct transfer between computers. The MS driver ony works with XP but maybe it can be made to work in 9x. The package is rather weird, many .man files (containing xml-formatted manifests). I found a link to it
here.