If this is indeed the real One M9 Plus, it appears that HTC has equipped it with a physical home button which, if previous rumors are to be believed, should include a fingerprint scanner. Other than that, the front of the alleged M9 Plus doesn't look too different from the front of the One M9, hosting BoomSound speakers, and what seems to be a pretty big camera. However, it's said that the M9 Plus will sport a Quad HD display instead of the 1080p panel that the One M9 is offering.
It's not clear if the One M9 Plus is the same device as the previously leaked HTC A55. According to @upleaks, the A55 could be launched as the HTC One E9 in China (though we also heard that it might be released as a Desire smartphone). Hopefully, HTC will soon announce these new smartphones (or this new smartphone, if it turns out to be just one) so we can put all the rumors and speculations to rest.
source: Weibo (in Chinese)