This is significant as some earlier releases were delayed by many months and such setbacks had become a fairly common occurrence with X.Org releases. In fact, there was more than a six month delay in just delivering a point release. Fortunately the new X Server development process is working out in everybody's favor and is good news for Ubuntu 10.10, Fedora 14, and other Linux vendors looking to ship updates with this new X.Org Server.
Among the changes for X.Org Server 1.9 are DRI2 improvements (a new authentication mechanism, buffer invalidation, etc), RandR 1.4 with per-CRTC pixmap support, code clean-ups, documentation updates, and much more.
Meanwhile, the X.Org 7.6 katamari release should be here by October. The xorg-server 1.9.0 release announcement can be found on the X.Org mailing list.