Using a 223 carbine buffer in a 9mm will this cause feed problems.

None at all.  I've owned two 9mm AR's (one Colt jam-o-matic and one Olympic) and used .223 buffers in both of them.  The problems I had with the Colt POS had nothing to do with the buffer at all, just a poor design.

Nope.  I've got them in two rifles.

In the Colt system the 9mm heavy buffer was designed and implemented for a good reason.  The extra mass slows down the cyclic rate, which is directly related to reliability, and especially the longevity of your components.  Heavier is better.

If you are looking for a lower you can quick change between calibers and not worry about buffers.....run a 9mm buffer in everything.  I have been running a 9mm buffer in my 223 for almost a decade.