I have no doubt about Bayern winning the league this season. Imagine with 9 point difference, that mean they have to lose like 3 match for Leverkusen to meet them. Even if they do what is the assurance that Leverkusen will win all his matches as well.
Bayern Munich now have a good points gap with Leverkusen and periodically Bayern Munich are performing better as the competition progresses but it looks like Bayern Munich will at least win the league title this season. Last season Bayern Munich were beaten by a few points by Leverkusen, now beating Bayern Munich this season and securing the league title will surely be sweet revenge for Bayern Munich. I want to see Bayern Munich win the league title this season because their best striker Harry Kane has not won any league title or Champions League title in his football career so far so this is going to be his first league title win for Bayern Munich and he will surely celebrate it well.
Leverkusen still keeps winning games, not like they are bad in some kind of way, they are very good too. However, since Bayern Munich ends up winning their games too, the gap isn't getting any smaller which is why it is causing some problems. I am not seeing any type of mistakes on Bayern Munich to be made this season, for whatever is left, they are going to either keep winning, or lose less points than Leverkusen, and just be the title winners once again.
Leverkusen could be upset that they missed their chance, but they should be happy that they used just 20% of what Bayern uses financially and kept them on their toes. When you are the underdog, chasing is what you do, and they should be proud with what they did this year.