Yes, the Panasonic Lumix G9 II is compatible with the Sony SF-M Tough Series 128GB SD UHS-II.
Panasonic Lumix G9 II's SD slot accepts this card directly. Sony SF-M Tough Series 128GB SD UHS-II is V60 class. Clears: MP4 4K30 LongGOP (72 Mbps, requires V10); MOV 4K/C4K LongGOP (200 Mbps, requires V30); MOV 4K/C4K ALL-Intra (400 Mbps, requires V60). Does not meet the floor for: MOV 4K/C4K ALL-Intra (top tier) (600 Mbps, requires V90). No setting or firmware update changes a card's rated speed class.
Limitation
Cannot record the camera's top-tier 4K/C4K ALL-Intra mode (600Mbps) — requires Video Speed Class 90 or higher. Works for lower-bitrate 4K/C4K LongGOP and ALL-Intra modes this card's class clears.
“Motion pictures with 400Mbps or less: External USB-SSD, SD memory card with Video Speed Class 60 or higher Motion pictures with 600Mbps or less: External USB-SSD, SD memory card with Video Speed Class 90”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)