Hi Andrew.
I don't use the "satellite" mode on the 910, but I believe that if you do, the sub band does transmit. You will have to check that for yourself.
Let me explain my own method for what you are trying to achieve.
I use WISP, by Chris Jackson G7UPN. It works very well, and is the only software, apart from PB/PG, that can be used to talk to the 9K6 satellites. You have to be able to uplink to request directories and subsequently, independently, download and read the files of your choice. If you don't do this, you may not receive complete files, which may also be compressed/zipped. There are lots of other files created on the satellite that are of no use to us, the basic user.
My 910 is permanently in 9K6, it shows on the display all the time. The figures 9600 have to be in the display. This means that I can upload files, request the directory and download files from GO-32 and AO-51.
Even in 9K6 mode, although not transmitting, I can still monitor the TLM/KSS files from AO-16 and the packet from the ISS.
For the above, all I do is put a cable in the extension speaker socket at the back of the 910 and the other end in to the TNC, an AEA DSP2232.
If you wanted to uplink to the ISS, you may have to change from 9600 to 1200 in the display. The best software for that purpose is UISS, written by Guy, ON6MU.
Remember to remove the audio jack used for 1K2 reception, from the 910 so that you can receive 9K6 data again.
If you are considering tracking with azimuth and elevation equipment, I can highly recommend HalloSat, written by Gerd, DB3DH.
All the above works for me, so it should do the same for you too. The only difference is our TNCs.
I hope the information is getting a little bit clearer for you Andrew.
73, Dave.