In Meditations , Marcus Aurelius makes several references to Zeus.
And so accept everything which happens, even if it seem disagreeable, because it leads to this, to the health of the universe and to the prosperity and felicity of Zeus (the universe).
Aurelius used the name Zeus to denote a form of universal ordering and reason or even the universe itself.
Why didn't he use the Romanized Jupiter instead?
It's because he wrote his meditations in Greek. There was a Grecian renaissance, a fashion for classical Grecian education (and facial hair), starting with the second century AD. His idea of Zeus is also indebted to the Greeks.