I've sent an e-mail to nokia-support to ask for HD-Voice support in the future.

The first response was that she does not know if the N9 will get support in any future firmware but she will talk to the dev-team and will send me the answer.

Some days late, she sent me a second e-mail with the surprising answer, after she having talked to the dev-team the N9 already supports HD-Voice assumed the network supports it.

Can anyone confirm this statement? My operator didn't support HD at the moment but I will change the operator if the N9 supports HD-Voice :-)