Edit 2: We're now looking at a Monday / Tuesday release for us, but no specific time due to proximity to Mojang release.
Edit: Mojang has delayed 1.9 until at least Monday 29th. This thread will be updated later in the week with our plans.
As most of you are no doubt aware of by now, Mojang has published Minecraft 1.9-pre1, and intends to follow through with the final 1.9 release on Thursday the 25th of February.
We intend to follow similarly and release 1.9 versions of Bukkit, CraftBukkit, Spigot & BungeeCord at 10:00pm UTC the following day, Friday the 26th of February.
In terms of release information, everything mentioned in the old thread (apart from the date) is still very much accurate. Some additional changes not mentioned there however include a rework of the Sound and Biome enums which may affect (and break) plugins that use these APIs. A full copy of the Bukkit 1.9 API (for developers) will be pushed to git either today or tomorrow. Interested developers will have until Tuesday to review or pull request, but please note that it may be force pushed to frequently.
Versions of whatever we are currently working on will be on the public test server (as per usual), and we encourage you to give it a look and submit bug reports. Server information and details for submitting these reports are in the last announcement.
We will also be looking at some official events on TeamSpeak etc in the hours leading up to release, so check the homepage regularly for more details.