Any chance you'd disable / uninstall [VirtualCD] and see if it makes any difference.
I completely disabled it via End Task, but I haven't tried uninstalling it. However, when MC 9-beta was first released, I didn't have VirtualCD. At least I don't think I did.
I just tested this on a co-worker's computer and did not haver the problem. Below is her system info.
Media Center 9.1.226 -- C:\Program Files\J River\Media Center\
Microsoft Windows XP Workstation 5.1 Service Pack 1 (Build 2600)
Intel Unknown 17 MHz MMX / Memory: Total - 522 MB, Free - 266 MB
Internet Explorer: 6.0.2800.1106 / ComCtl32.dll: 5.82 (xpsp1.020828-1920) / Shlwapi.dll: 6.00.2800.1106 (xpsp1.020828-1920) / Shell32.dll: 6.00.2800.1145 (xpsp2.021108-1929) / wnaspi32.dll: N/A
Ripping / Drive D: Copy mode:ModeBurstBigBuffer CD Type:Auto Read speed:Max
Drive E: Copy mode:ModeBurstBigBuffer CD Type:Auto Read speed:Max
Digital playback: Yes / Use YADB: Yes / Get cover art: No / Calc replay gain: Yes / Copy volume: 32767
Eject after ripping: No / Play sound after ripping: No
Burning / Drive E: CDWRITER IDE3212 Addr: 1:0:0 Speed:32 MaxSpeed:32 BurnProof:Yes
Test mode: No / Eject after writing: Yes / Direct decoding: Yes / Write CD-Text: No
Use playback settings: No / Normalization: None
I think I also tried the unstalling 9 and 8 and reinstalling. Nothing.
I'll try uninstalling VirtualCD to see if it's the problem.