Hello and thanks so much for your feedback!
I'll adjust the "auto buy levels" function accordingly, it makes more sense to work the same way the "level all cats button" does. This way you won't have spent a Blessing for nothing :D
Achievements would totally be a great addition, you are right! I'll have to think of a way on how to implement them, what kind of achievements there are and what kind of rewards they give you.
About the "10th level bug", I'll look into it, usually the level cap is 9, as you might have noticed.
And yes, so far being blessed is the highest layer of prestige, but there is more to come, no worries!
I have already worked on adding more content and features, it will take some time to test it out and get it to work. In the meantime I hope you'll have fun with everything the game has to offer so far :)
I want to thank you again, feedback like this really helps so much.
In any way, have fun and stay healthy!