change https port on server side / multi SSL profile, SNI/ https from client to F5 and from F5 to server

In your first iRule you're using a redirect, which sends a response to the client telling it to come back to the specified URL. You're specifying URLs with the backend ports, so you're VIP isn't going to be listening for these.

In your second iRule you're just changing the Host header in the request, which does not change the physical port.

I'd recommend that you create a separate pool for each application. Example:

site1_pool = server IP(s):8443
site2_pool = server IP(s):9443
site3_pool = server IP(s):10443

Then in your iRule switch between the pools based on the requested Host:

when HTTP_REQUEST {
    switch [string tolower [HTTP::host]] {
        "www.site1.com" { pool site1_pool }
        "www.site2.com" { pool site2_pool }
        "www.site3.com" { pool site3_pool }
    }
}

By the way, you can do all of this in LTM policies instead of iRules.