Yes, the DJI Mic Mini is compatible with the Nikon Z9.
Nikon Z9 has a 3.5mm stereo mini jack external microphone input. DJI Mic Mini includes a 3.5mm TRS analog camera output. Direct plug-and-play connection, no adapter required.
“Nikon Z9 includes a 3.5mm stereo mini-pin jack external microphone input per Nikon published product specifications.”
“DJI Mic Mini Camera Audio Cable (3.5mm TRS)”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)