Enable and disable HTTP2 in irule

You could try an iRule that checks if the request is HTTP2 and then change the pool based on that like this:

when HTTP_REQUEST
{
    if{[HTTP2::active]}
    {
        pool http2_pool
    }   
    else
    {
        pool other_pool
    }
}

Here is the documentation for that command. It says it was implemented in 11.4.

If you have any more questions, I am sure I can help.