Can Yasuo's windwall block Cassio's R?

Can Yasuo Windwall block Azir R & Riven R?

no, Cass R is an AOE ability, I do not think its considard a projectile

Edit: I should have clarified, anything that that is a labeled as a projectile can be blocked by Yas Wind wall, your example of Orianna's ball is a good one, but I am thinking that when the ball is moved around with Orianna's q ability during that time its considered a projectile

No. You can determine whether abilities are projectiles or not based on their travel time.

If they have no travel time (they hit everyone in the AoE at the same time), they are not a projectile. This is how Cass ult behaves; no projectile, no block.