DCP-o-matic

Probably a dumb question but can DCP-o-Matic create an HDR (or Dolby Vision) DCP providing of course the source file is HDR (or Dolby Vision)

I wouldn't call it that. Short answer: No.
Longer answer: You wouldn't be able to make a proper SDR DCP out of an HDR source file either. "Trimming" is necessary beforehand.
A search on the forum will show more.

OK I understand, it's a limitation of the DCP projector. HDR is more of a TV format and not a cinema format?

There are specific systems and specific DCPs made for them that support HDR. Dolby and Eclair has worked on them. The LED cinema screens are also in that group of systems.
Besides that, the dynamic range of cinema is "extended", but not "high".
DCP-o-matic wouldn't create such DCPs from an HDR video file. You need to have an SDR source, otherwise the result will be that "flattened" image you get when you use an SDR monitor to depict an HDR file without the relevant look-up-table.

Thanks for the info!