@Faraz Welcome to Microsoft Q&A forum!
I want to cover an area of 9 meter x 5 meter using Azure Kinect.
The maximum depth distance depends on the FOV mode you operate the depth camera in.
Did you check the Azure Kinect DK hardware specifications already?
More information from the related question:
You can use simple trigonometry to calculate the width of the FOV for a specific distance from the camera.
Specifically looking at the 120 def FOV. You can split the FOV into 2x 60 deg (angle between acute and hypotenuse) right angle triangles with the opposite 5ft in length (1/2 of 10ft). The acute is calculated as tan(60) = 5 ft / a -> a = 5 ft / tan(60) = 2.88 ft. So the Azure Kinect camera needs to be at least 2.88 ft from a 10 ft subject to completely visualize the subject.