Hi Janine,
Aside from adjusting the memory size allocated to eclipse in the startup bat file that you pointed out there is an open defect for the studio 9 debugger. The bug ID is CSCuc70970. Cisco is still reporting that there is no fix or workaround in the bug toolkit but the problem is really a missing jar, which I have attached.
Place the jar in %CVP_HOME%\CallStudio\eclipse\plugins\com.audiocorp.studio.debug.runtime_9.0.1-SNAPSHOT\CATALINA_HOME\webapps\CVP\WEB-INF\lib and restart studio.
I hope that this helps. (I love that I am able to help you for once instead of asking you for help)