There are number of methods to serve up the VMware Cloud Foundation (VCF) 9.0 software binaries for hosting an offline depot from running a traditional web server as outlined in the official VCF documentation to running a simple 1-liner Python command to serve up the files directly to the VCF Installer.
If you happen to have a Synology in your lab, you can add the WebStation package and quickly setup a VCF Offline Depot without much hassle.
Note: To download the the required VCF 9.0 software binaries and metadata, you will need to use the new VCF Download Tool (VCFDT) and a valid Broadcom Download Token.