If you upgrade to v10d straight from v9.x, you will HAVE to upgrade the Remote Agents at the same time. See the SCL at http://seer.support.veritas.com/docs/278254.htm
If, however you do it in stages, to v10, then to v10d, the v10 media server WILL talk to the v9.1 RAWS, See http://seer.support.veritas.com/docs/264484.htm