Okay, It's been 1 minute since I posted my previous post.
I've opened the game again and the problem is gone. . .
I can play the game normally and there's no 90 minutes countdown nor the BUY NOW...

I have the exact same problem.
I redeemed the game from Mojang's site. downloaded it, installed it, connected it with my xbox account ( the email is the same for both windows 10 and xbox acc )....