I'd be very surprised if it worked directly out of the box.
The Kenwood radios that use this mic have the following pin-out on the RJ-45 mic connector.
Pin No. Name Function
1 BLC MIC key backlight control
2 SB Power output of switched power supply DC13.6V±15%, 200mA typ
3 E Ground
4 PTT/TXD PTT: PTT input, TXD:Serial data output
5 ME MIC ground
6 MIC MIC signal input
7 HOOK/RXD HOOK: Hook detection, RXD: Serial data input
8 DM MIC data detection
KMC-9 has a mic impedance of 600 ohms.
PTT is digital.
If all that matches the wiring and specifications on the Yaesu, then it might work, if it doesn't, it sounds like a whole lot of work to adapt it.