Eisenhower was told that American scientists were working on fission bombs in September 1942. (General G.V. Strong told him, because he was telling Eisenhower to destroy Norsk Hydro and wanted him to know why.) I don't know if he was kept much abreast of the progress, though — I doubt it, as practically nobody was outside of Roosevelt's very small and selective Top Policy Group. The Top Policy Group, however, did include the Secretary of War (Stimson) and the Army Chief of Staff (Marshall). And, of course, President Roosevelt himself.

As for waiting, I've never seen it contemplated. The bomb was still in a terribly nascent state in 1944. The first uranium was getting enriched early in the year but they were having immense problems with it. The first Pu-production reactors didn't go live until the fall of 1944. It is hard to find estimates from 1944 as to when people thought the bombs would be ready; the most optimistic ones I have seen suggest that some thought that they might be ready as early as Thanksgiving 1944 or Easter 1945.

Roosevelt apparently did ask Groves about using the bomb on Germany in December 1944, but this is the only record I've ever seen of someone trying to see whether it could be used in Europe.

It is worth noting that even in the case of Japan the bomb's schedule was not allowed to influence invasion plans. This was one part because of secrecy — the invasion planners were not generally told about it until after the Trinity test in July 1945 — and also because of fears that the bomb wouldn't pan out (which also wasn't clear until the Trinity test).