Unity Android and HDMI

Is there any support in Unity Android to have output shown in HDMI?

The HDMI output is managed by Android OS at lower level, thus any thing rendered by Unity should be available through HDMI.

Yes HDMI out works if your phone can do it

Android OS does not support HDMI output. Some devices, such as HTC EVO 4G, have taken it on their own to develop their own HDMI output support. These are proprietary to each manufacturer and the API's are often not publicly documented. As there is no standard for the HDMI outputs I highly doubt that Unity will support each device independently.