You can use internet explorer 9 without any issues as long as you disable XSS filter.
Either firewall will let you connect to port 8000 or it will not. If you are experiencing sporadic issues then it could be a network issue. Try recreating your linux network. Stop the VM. Change MAC address of your linux VM to anything (just add 1 or something). Restart VM. System will give you few messages on the next boot, as new hardware would be detected. Choose to remove the configuration of the old MAC address and configure the new one (during the boot). Also reboot your router just to rule out any glitches there. See if that fixes sporadic issues.