All We Have Left by Wendy Mills

Now:
Sixteen-year-old Jesse is used to living with the echoes of the past. Her older brother died in the September 11th attacks, and her dad has filled their home with anger and grief. When Jesse gets caught up with the wrong crowd, one momentary hate-fueled decision turns her life upside down. The only way to make amends is to face the past, starting Jesse on a journey that will reveal the truth about how her brother died.

Then:
In 2001, sixteen-year-old Alia is proud to be Muslim… it’s being a teenager that she finds difficult. After being grounded for a stupid mistake, Alia is determined to show her parents that that they must respect her choices. She’ll start by confronting her father at his office in downtown Manhattan, putting Alia in danger she never could have imagined. When the planes collide into the Twin Towers Alia is trapped inside one of the buildings. In the final hours she meets a boy who will change everything for her as the flames rage around them…