iRule for pool usage instead of VIP(s)

Yes, you can try LTM policy. Regarding need of VIP for redirection, could you please confirm the port of VIP where the request will hit? Now if user will access http URL with default port and you want to redirect that request to the pool as per irule, then VIP with port 80 should be sufficient. Else if you want to redirect user request from http to https first then redirect it to the pool, in this case you would need two separate VIPs i.e. one will listen on port 80 and other will listen on 443. Hope it helps to achieve your requirements.