Circumstantial may mean there's a question mark, but it doesn't mean "no evidence at all". Certainly Russia would gain greatly from a President who was less willing to stand behind the US's European allies, and who, all in all, would likely represent a more inward-gazing US. Russia has no hope in hell of ever militarily dominating the West, but if it can divide, then it gains a great deal of strategic space.
Clinton's victory means the general policy towards Russia that has, by and large, been the US's strategy since the Truman Administration, remains intact, so it is clearly in Russia's interest to try to help the person that at least might represent a break with that strategy.
Yes, it is circumstantial, and there is a possible counterargument that not even Putin actually would want someone as potentially unpredictable as Donald Trump in the White House, but I still lean towards Russia wanting a more isolationist Administration in the White House, much as it wants the European Union and NATO to be weakened. These three entities; the US, the EU and NATO represent significant checks on Russia's ability to project its power, and if any or all of them can be weakened or eliminated, it is of enormous strategic advantage to Russia.