How to make an object impassable?

Kinematic doesn't have a collision response, it doesn't respond to forces. That's the whole point of a Kinematic body.

 

This is such a basic question I have to suggest that you follow a starter tutorial on Unity Learn for 2D physics such as this one here.

It's not about a wall, it's about something that doesn't pass through a wall. This, of course, depends on what you're using for your "player". Typically that's a Rigidbody2D set to Dynamic body-type. Dynamic body-mode has a collision response (bouncing, friction etc) as well as stopping overaps or resolving them.

Things that don't move are Static so either add a Rigidbody2D and set its body-type to Static or don't add a Rigidbody2D (just the Collider2D) and they are implicitly Static so won't move and, like everything else, cannot move because you should never modify the Transform.

The question back to you is, how are you moving the "player".