Maybe yes, maybe no.
The Kai appears briefly in an "orb vision" in DS9: Accession.
Sisko keeps walking. The lights of the Promenade seem DIMMER now. The
background hum of the station has dropped away. The feel is ominous...
strange... he hears the RUSTLING again, whips around toward the
Disturbed, he turns to continue walking -- and finds himself
Sisko couldn't be more surprised.
DS9: Accession - Final Draft Screenplay
According to Memory Alpha (referencing an anecdote from the DS9 Companion), an earlier version of the draft script indicated that Sisko had concerns that it wasn't simply a vision but an attempt by the real Kai to contact him telepathically.
In ultimately unused dialogue from the second draft script of
"Accession", Kira suggested to Sisko that the vision of Opaka he had
seen was actually an attempt by Opaka to telepathically communicate
with him. Skeptical of this theory, Sisko remarked, "We don't even
know if she's still alive," which Kira then acknowledged.
Memory Alpha: Opaka