The dethroned Spanish and European champions are the most successful Club World Cup side and joint favourites in 2025.
Nidal Umairah tried to talk to Israeli soldiers before he was attacked, and then killed, along with his brother Khaled.
While the ruling does not order Khalil's immediate release, it does undermine the US government's case against Khalil.
Major General Scott Sherman says National Guard troops have been trained to make detentions but have not done so yet.