TMH If your pool members are expecting to receive HTTPS traffic on 8443 then you would absolutely need a SSL Profile (Server) configure on the virtual server. It is possible to have the server configured to received decrypted traffic on 8443 but you would have to verify. An easy way to validate if the server is expecting HTTPS traffic is to perform a curl from the F5 directed at the server's IP on 8443. The command should very similar to the following with the appropriate informaiton filled in.
curl -Ivk "https://<server_IP>:8443/"
If you know the host field that the server is listening for you can do the following instead.
curl -IvkH 'Host: <website_host>' "https://<server_IP>:8443/"
After running either of the se commands you should see the SSL certificate in the output if the server is expecting HTTPS communication on this port.