No. ABMaterial requires jetty. It can only be deployed on a VPS which can run java as the project.jar file must run to use the WebApp This is not a ABMaterial specific requirement. All B4J Webapps need this. Best to first read and understand https://www.b4x.com/android/forum/threads/webapp-web-apps-overview.39811/ before checking out ABMaterial, as it completely relies on this. ABMaterial is just an alternative UI. All the inner webapp workings are pure B4J.
I didn't, but our apps only have a max of 50 concurrent sessions and I hadn't had a problem yet.
Maybe better ask this as a new question in the forum, directed to all B4J WebApps, as people who have done stress testing but do not use ABMaterial may not see this.