Opmantek has released a new NMIS9 Virtual Appliance; it may be downloaded here:
https://dl-nmis.opmantek.com/Opmantek-20200731-VM9-Centos7.2003-2-64bit.ova
Release notes: Opmantek NMIS9 Virtual Appliance: Release Notes
Installation & Getting Started: Opmantek Virtual Appliance: Installation and Getting Started