I believe that's still the contingency plan in the unlikely event that they have to evacuate the ISS in the period between Starliner undocking and Crew-9 docking.
Yes it is and it is not the first time having such contigency plan.
Quite recently there was a Soyuz with crippled cooling and the contingency plan for the American astronaut that came with it was to evacuate via Dragon if there was an emergency before new Soyuz arrived.
From the press conference today, they stated that there is already an extra SpaceX suit on the ISS. Both astronauts have tried it on, and it fits. They will be bringing an additional empty suit up when Crew launches.
Oh, good. Previous proposals included having them return in a Dragon unsuited.[1]
[1] https://futurism.com/stranded-astronauts-spacex-boeing-space...