Yeah OK :) wglgears does render albeit incorrectly due to the twitchiness.
But I do think it's related to x11-servers/xorg-server-1.7.7_1,1 as that's what 9.0-CURRENT and 8.2-STABLE have in common, and no opengl games render on them.
8.2-RELEASE with xorg-server-1.7.5_1,1, however, is fine.