Yes He knew the result of their choices. He also had the plan of redemption since before He created them. He could have made us robots obedient to His will with no mind of our owns. That was not His plan. If Adam and Eve had not sinned, I do not know the result. I assume that just as sin came through one man that perfection would have as well. This is just my belief. Could someone down the line have sinned if Adam didn’t? I don’t know. However, God knew that Adam and Eve would sin and He had the plan to redeem mankind.
It seems that if He hadn’t created the temptation, then there would be no sin. We wouldn’t be robots, if we didn’t know, would we? Just blessed beings, like those in heaven. Do you believe that God knows the outcome of His plan?