use phone video in 16X9 sequence

You can definitely create that soft-focus background effect in Premiere Pro! Once you have your phone clips in the timeline, follow these steps:

1. Duplicate the Phone Clip: Place a copy of the phone clip on the track below the original (or whichever track you'd like to fill the background).
2. Scale Up the Background Clip: Select the lower clip and increase its scale in the Effect Controls panel until it fills the screen.
3. Apply Gaussian Blur: Go to Effects, search for Gaussian Blur, and drag it onto the scaled-up background clip. Adjust the blur amount until you get a soft-focus look.
4. Color Correction (if needed): Adjust brightness or color on the background layer to make sure the subject stands out.

This should give you that soft-focus effect to fill the sides while keeping the focus on the main image. Hope this helps, and feel free to reach out with any other questions!

Copy the phone clip to a track above the clip.

On the lower track, increase the scale to fill the black and add the blur effect.