Yesterday the version 3.9.0 for the SAP Cloud SDK was released including the OData VDM Generator. However the corresponding Maven Plugin is still missing. Is there some reason for this or when can we expect this to be released? After all it contains an important bugfix.
Version 3.9.0 of the plugin should also be available since Thursday, like the other artifacts, see https://search.maven.org/artifact/com.sap.cloud.sdk.datamodel/odata-generator-maven-plugin/3.9.0/maven-plugin
The indexing on Maven Central may sometimes take a bit longer, perhaps this is what you experienced. Please recheck if the issue persists.