Sorry, it's not been abandoned, it's just not possible.
Before everyone leaps on me, I should point out that there are two kinds of Bluetooth – it's not all the same.
The H9 uses Bluetooth 2.1, sometimes known as "classic." This is commonly used for headphones, and has no general support for MIDI. The H9 does send MIDI over it, but there is no standard for this.
The other kind of Bluetooth is Bluetooth 4.x or 5.x, otherwise known as Bluetooth Low Energy or BTLE, as it is particularly focused on battery powered systems. This does support MIDI, but was introduced after the H9 was developed so is no help to us.
.
