How many days after the pour, should I remove the bracing of the wall ? Thanks

Depends on the project - If it is a basement relatively protected from wind I would say 48 hrs. If it is a second floor wall in an open field in a windy area, you may want to keep them on until the roof is attached.

Where is this being built and what are some details?

We remove braces next chance we get, which is usually the next day. Sometimes we will remove plywood and stuff after lunch.

On a commercial project, precast plank was set on our 8" ICF walls with some lintels as small as 11" deep, after just 3 days in the winter. I think the engineer stuck his neck out really far.

How rapidly concrete sets and gains strength is highly variable - depends on the concrete mix and the temperature. On the other hand, once a wall has set, you don't need much strength just to remove bracing.