Do we need to open the port 9000 through the firewall for the Application Server communication ?
No, you do not need to open port 9000 as this is a virtual port number.
The physical port you need to open is port number 7163 and it always needs to be opened in "bi-directional mode".
The port number 7163 will be used each time SSA is involved in the communication,that is for communication with WCC, Client utilities, APIs and SDK.
Port 7163 is also used when the System Agent is configured to use Dylan protocol ( not default AFM protocol)