Almost anything is possible. I think a major constraint to evolving intelligent life is the fact that it requires large heads, which make birth difficult. The marsupial solution of giving birth to very small underdeveloped babies and completing development in an external pouch soleves this problem nicely. Also, hopping motion is more efficient than our clumsy walking, and leaves the upper limbs free to develop into hands for tool use. So I think it's likely that most intelligent life forms in the universe are basically kangaroos.

That doesn't answer the question of where they are, though.