Sorry to hear about your flooding damage. 

You won't be able to connect the H9k directly to the AxeFX3 via the USB B ports on both units since both of the units would be expecting a USB host (the computer) and neither would be able to fill that role. If you use Mac, you should be able to create an aggregate device and could route the audio between the two units using a DAW. You would also have the option of using the analog I/O in combination with the S/PDIF or AES XLR I/O. 

I believe there are other forum users who use both units together so I'll let them chime in.