Yes. MIDI connections and signal transmission are available.

MIDI messages are sent when you use buttons or knobs on the DJM-A9. You can send MIDI clock messages too.

For details on output terminals, connections, etc., see the [USB/MIDI Section] in the Instruction Manual.

The Instruction manual is available [here].

The list of MIDI messages is available [here] 

Note: The DJM-A9 does not support the input of MIDI signals.