I don’t think you can indict a sitting President, can you? The Feds better get this done but I won’t hold my breath.
I believe you are correct. Nixon, you may recall, was an "unindicted co-conspirator" in Watergate. If such a tag were put on Obama after he assumed the Presidency, it would require impeachment by the House and conviction by the Senate to remove him from office. With both houses controlled by the Dems, I don't think it is likely that would happen. And even if it did, it would be "welcome President Biden."
That said he wouldn’t be President until Jan 20, 2009. I assume a president-elect would have no Constitutional protection, but I doubt he could be tried after 1/20/09 regardless of when the indictment came.