The Last Jedi is actually referenced in the first paragraph of The Force Awakens opening crawl:
Luke Skywalker has vanished.
In his absence, the sinister
FIRST ORDER has risen from
the ashes of the Empire
and will not rest until
Skywalker, the last Jedi,
has been destroyed.A fitting title I must say! (Before the release of the movie everyone was speculating who were the last Jedi, was the title plural, when the answer was there all along)
I wonder if the title for Episode IX is in the crawl from The Last Jedi?
The FIRST ORDER reigns.
Having decimated the peaceful
Republic, Supreme Leader Snoke
now deploys the merciless
legions to seize military
control of the galaxy.
Only General Leia Organa’s
band of RESISTANCE fighters
stand against the rising
tyranny, certain that Jedi
Master Luke Skywalker will
return and restore a spark of
hope to the fight.
But the Resistance has been
exposed. As the First Order
speeds toward the rebel base,
the brave heroes mount a
desperate escape…