According to a source, B&H, the HTC One M9 will be released closer to the end of the month. Specifically on March 25 with $649 price tag.
The launch date and the price tag were quickly removed from the listing by the retailer, so probably that coulb be the actual release date of HTC One M9. B&H has a stellar track record as a retailer, so there is little reason to doubt its listing.
HTC One M9 made its official debut last Sunday during MWC. I guess that for more informations on this we will have to wait.