Nintendo has released a late 2009/2010 release list of first party titles and the manner in which Golden Sun is listed gives hope for a 2009 release in Japan.
The game is listed alongside The Legend of Zelda: Spirit Tracks as "TBA" for a Japanese release - but interestingly Spirit Tracks is a confirmed Holiday 2009 release in the USA.
With Spirit Tracks dated to hit America before Christmas it's likely it will also land in Japan before the end of the year - and one that only leaves one other "TBA" game on the list - Golden Sun.
Perhaps that will do the same? With the game just announced Nintendo are keeping quiet on it - but indications are that the team have been working on it in secret for some time and it is quite far along in development.
Sadly, even if it does get a late 2009 release in Japan Western fans of the series will have to play the waiting game - it's listed for a 2010 release in America and isn't listed for a European release at all yet, though Nintendo folk assure uys at RPGSite it will be heading to Europe.