Are you unofficially a PhD holder after passing viva voce for PhD?
At my American university, the process of officially getting a PhD was tiered.  It went something like this:


No claim to being a PhD until after successfully defending.
Some informal claim to being a PhD after successfully defending.  The committee members would usually make this explicit by congratulating the successful defendee with "Dr.".
A weird quasi-official claim when the university's official degree-completion tracking system formally acknowledged that the student has officially met all degree requirements and is scheduled to receive their degree at graduation.
Official claim upon graduation (whether or not attended).
Verifiable official claim once you have the piece of paper, which may be several weeks after graduation if not attended.


Folks I knew were reluctant to claim PhD-status until graduation, but I think that hiring managers in academia and industry tend to find the caveat of not having been through the ceremony to be fairly trivial.  Family and friends are especially unlikely to care about that caveat, except as an excuse to talk about how exciting graduation'll be.