It is expected (and in nearly every case not required) that the openvassd isn’t listening on a TCP port by default. The only service which should listen externally on a TCP port is the gsad of the Greenbone Security Assistant (GSA):
The default port of the GSA is either 443 or 9392 (depending on the permissions of the user running the gsad daemon or the availability on the 443 port) as described in GitHub - greenbone/gsa: Greenbone Security Assistant - The web frontend for the Greenbone Community Edition
One additional (but not directly related) note to this version:
if you compare this version with the recent releases of OpenVAS / GVM 9 listed here:
you can see that those are quite outdated. Its strongly recommended to keep your installation up to date.