I meet a curious solution from cisco DOC, if I want to use 2*HWIC-4ESW same time , I must stack both cards,
how to avoid it , I really need 8 ports on it , do I have to buy HWIC-D-9ESW ?
If You want to use both hwic in same router You must stack them, otherwise one of them wan't work.
For what I now, there is no work around for that.
So Your only option if You require 8 ports is, as You self suggest, is to buy a 9 port module.