According to Adobe's published list of supported cameras, that model requires Lightroom 6 .14. If you want to continue using Lightroom 5.7, it will be necessary for you to download the free standalone DNG converter and use it to convert your images to the DNG format and then import those DNG files into Lightroom 5.7.
despite the G9 being listed as compatible.
What Jim said.
Can I ask where you saw it being listed as compatible?
This table lists supported cameras Cameras supported by Camera Raw but each column shows the minimum version of the various flavours of Lightroom required to read Raw files from that camera.
And just FYI, the little chart snippet that I posted was extracted from that table that John posted a link to.