Regardless if you use a docker package from the distribution’s repos or docker’s repos, it would be managed by yum/rpm, unless a binary installation was done on the host or a different package manager was used (if they exist on CentOS).
I don’t use rpm based systems, so I can’t tell you how to list the installed packages, but if your command above indeed lists the installed packages, then why not grep for lines that include the string docker like this yum list installed | grep docker.
Furthermore, please share the output of docker info.
Maybe you have Podman and not Docker and you have “docker” as an alias to podman. At least I have seen it to happen more often on Red Had based operating systems. The alias could be in a bashrc or profile file depending on what shell you are using.