The Soviets had no intention of telling their own people even if the West knew about it. Back then, the internet was in its infancy and no Soviets had access to it.
As for 9/11, the use of four planes was deliberate to make sure every American knew it was terrorism on our shores. And every American was angry and filled with resolve against the people who hated America and attacked us, so much so that...
...just seven years later they put one of them into the White House. All thanks to s complicit democrat/communist media/entertainment/academia propaganda complex.
It is very easy to contain the spread of information while sustaining an illusion of free and open flow of information, even though it is possible for accurate information to flow around the globe in seconds, that does not mean the right things are covered, or that the events covered, are covered honestly.