Screen, battery, rear cover and camera modules have individual guides; this budget model has its own parts list.
What to check before buying
Cover and screen
iFixit lists separate procedures for the rear cover and front screen. A crack on one side does not automatically call for the other assembly.
Battery and cameras
The 9a has an exact-model repair manual and guides for the battery, front camera and ultrawide camera. Pixel 9 parts are not assumed to fit the 9a.