Kubrick shot his movies with both the theatrical and the 1.33:1 aspect ratios in mind : you can see this in "A Life In Pictures" - video monitors on set at EWS that Kubrick would use to view filming images were marked with black bars to delineate where the additional 1.33:1 image appeared at top/bottom of the image.
No. Stanley Kubrick, and most other feature film directors, compose their films for the primary exhibition venue, the commercial cinema. Protecting
the full camera aperture for eventual video transfer is usually the job of the cinematographer/camera operator.
Video monitors have been used on film sets as a tool for directors for years. Small video cameras are placed on the film camera just for this purpose. During the time EWS was made, ALL of these monitors would have been 4:3 with either 1.85 or 2.35 framing marks on the screen.