Unfortunately BIG-IP 4.x iRules do not have the ability to do anything with the server response, they can only manipulate incoming requests. And as you surmised Rewrite Redirects only looks for http to rewrite to https.
I think you are going to have to wait for 9.x iRules in order to be able to strip the 9443 port out of the server response.
In the meantime, you could create a virtual server listening on 9443 that had a rule redirecting everything to 443, kinda kludgy but it would at least end up with the clients back on 443 where they belong. Just a one-liner would work:
redirect to "https://%h/%u/"
where %h is the current host and %u is the current URI.
Or even:
redirect to "https://a.b.c/%u/"
to ensure use of the host you want.
Denny
Nimbostratus
