Plan 9 is very multi-user, namespaces are actually one component in how it is multi user specifically. A given terminal may be designed to only have one user on it but CPU servers are still multi-user multiplexers, that part has not been given up.
Yes, by multi-user i meant, plan9 doesn't have the unix/linux user model, but rather "multi-user" is done with the namespaces. Container people would be more familiar with the plan9 way.
