Got rear ended..

This lovely person rear ended me at a stoplight going about 10 mph because they were changing songs on their phone. The impact shut my car off and chirped my tires forward a few inches, I had my foot on the brake. Cosmetically the damage is minimal but that's not what I'm worried about. Since the incident my car is making a weird rattling/grinding noise when I lightly accelerate between 20-30 mph. It's coming from the front of the vehicle it almost sounds like a CV axle maybe. I just hope it's not the CVT. I have this person's info and they have already admitted liability but the insurance guy is giving me a hard time about this noise given the impact was from the rear.

Any thoughts or concerns, maybe advice?