The security headset (manufacturer Midland, product ID C732.06) is not compatible with the Midland G9 Pro walkie-talkie. This is confirmed by user reviews that explicitly state that the headset does not work with the G9 Pro. In addition, the G9 Pro uses a 2-pin standard Icom (S) connector for accessories, while the C732.06 headset has a different connector that is more compatible with older Midland models.
The MA31-L Security Headset from Midland is compatible with the G9 Pro and other Midland radios that support the 2-PIN Midland connector. It requires no additional configuration and can be connected directly for immediate communication.
The "MA 31-M Security Headset" from Midland is not specifically designed for Kenwood devices such as the TK-3701D. It is designed for Motorola devices, which means that it may not be compatible with Kenwood devices without customisation.
Depending on the brand it is compatible with these models:
CB radio stations Alan 42 and Alan 52. PMR stations (Walkie Talkie): Midland M24, Midland M24 plus, Midland M48, Midland M99, Midland G6 XT, Midland G7 XTR, Midland G8, Midland G9, TTi TXL-446, TTi TX-1446P, Alan HP450 Walkie talkie with 2-pin.
It is compatible but not recommended for motorcycling. Motorcyclists have special headsets that are designed specifically for them. Therefore, we believe that it is not recommended for your intended use.