No, not as an adult. Stalin was an atheist and did not believe in God.
From Wikipedia:
"His(Stalin's)Marxist government promoted atheism through special atheistic education in schools, anti-religious propaganda, the anti-religious work of public institutions (Society of the Godless), anti-religious laws and the fermenting of repression against religious believers. By the late 1930s, it had become dangerous to be publicly associated with religion."[352]
https://en.wikipedia.org/wiki/Joseph_Stalin
From Wikipedia:
"His(Stalin's)Marxist government promoted atheism through special atheistic education in schools, anti-religious propaganda, the anti-religious work of public institutions (Society of the Godless), anti-religious laws and the fermenting of repression against religious believers. By the late 1930s, it had become dangerous to be publicly associated with religion."[352]
https://en.wikipedia.org/wiki/Joseph_Stalin