Could you please verify that you need to have "Unique client identifier - BETA" enabled on the network you try to join it to before the 9300 will actually be visible in the Dashboard ?
I had some trouble with it today. But got it online eventually.
Now Im stuck in the other mode : Management. Where the switch cant be claimed to inventory. But if I use the API to claim it directly to a network, it only works if that network has "Unique client identifier - BETA" enabled. And that's not something you apparently can easily set on networks that do not already have switches in them (and of course an MX).