This was also posted previously as a possible fix for 9000 errors, it really depends on why you are getting them.
If you're getting frequent error code 9000 disconnect errors, try these steps to fix.
1. Head to http://www.microsoft.com/download/en/details.aspx?id=35
and make sure you are running the latest DirectX.
2. Right click the SWTOR exe file in your Electronic Arts/Bioware/SWToR directory, do this on the launcher.exe and the swtor.exe in the retail folder , select properties and choose compatibility mode for Windows XP Service Pack 3 / Vista service pack
3. Also in the compatibility tab run both of these .exe as administrator.
4. If you have access to your firewall/router, open or forward these ports to your IP:
5. Reset your modem/router and see if this helps.