While we can’t answer that question as far as a Western release is concerned, thanks to information contained with the pages of Famitsu magazine (pictured below), we know that the game will be available in Japan this September.
Naturally it would be wise to assume the game will hit the rest of the world sometime after that date. I suspect we will get a better idea for the worldwide release plans during E3 later this month.
We actually covered this scan a few days back, but it seems that some clever chap has translated the text to find the actual month of release.
There might be some hope on the horizon for Virtual Console releases of the NES Mega Man games for North America also. To celebrate this momentous occasion Capcom also stated that they will be releasing Rockman 1 in July and Rockman 2 in August on the Virtual Console.
In the meantime, why not check out all the latest Mega Man 9 media on our game page?