Guys, I have no knowledge on N9/50 BT subsystem, but there was a similar issue (i.e. once into sleep never wakes up) on n900. Don't know if it will be of any use, but one may want to look into kernel-power BT patch for mouse.

on the other hand HID input profile works OK on n900, I can't think of any reason it should not work on the newer kernel n9/50 has. Given the module is built of course