RNJack,
I am not sure why you chose to put the MCS on a separate VLAN, but usually we expect to have all of the Voice Equipment on the Voice VLAN; in this case VLAN 9. This reduced the need for traffic shaping and troubleshooting across VLANs.
With that said it shouldn't matter as long as traffic is flowing properly through the network and nothing is being blocked. It doesn't sound like anything is being blocked, which is good, but there is still a delay so it sounds like a traffic shaping issue.
Personally, I would recommend moving the MCS to the Voice VLAN to see if that resolved the problem, but if there is a security reason for it then we will just have to start looking at setting the switches up to give audio a higher priority through your network.
Thanks,
TE