When you say 9000, you should mean the configuration attribute fs.default.name or fs.defaultFS (new version). This attribute is a URI (including protocol, host name and port number) that describes the named node in the cluster.

50070 is actually the configuration parameter dfs.namenode.http-address in hdfs-site.xml, and the default configuration is dfs.namenode.http-address, which is the listening port of HDFS web interface.