Firstly, it's Lenin that he blames for Ukrainian autonomy - not Stalin. Secondly, Putin has evidently said that Stalin was a mixed blessing; he industrialized the Russian economy, and he defeated the Nazis, but the repression and murder he caused were wrong.
""The positives that undoubtedly existed were achieved at an unacceptable price. Repressions did take place. This is a fact. Millions of our fellow citizens suffered from them," Putin said.
"Such a way of running a state, of achieving results is unacceptable, this is impossible. We have not only lived through the personality cult but also witnessed mass crimes against our own nation."
So, apologies for misinformation.