Although it is not specifically made for the HP HDX 9430EF, this driver is working perfectly with windows 7 64bits edition.
Note: There is no native driver from HP for this computer and Windows 7
driver link : sp48925.exe
It was quite difficult to find a driver, but finally I’ve found it!
It allows your Motorola HT820 blueTooth headset to work with Win 7 X64
Motorola HT820 blueTooth headset quick start manual :