Michael, IMO, with the present GOP-majority Senate, either writing articles of impeachment or impeaching would play into Trump’s hands.
As for the Article I Section 9 clause, it’s ambiguous enough that it can be read as saying:
1) indictment must follow removal from office, or
2) that because impeachment’s effects end with removal from office, later indictment will not be double jeopardy.
The talk about a sitting president’s being too busy to indict serves the GOP’s purposes. It’s also simplistic enough for Trump’s voters to understand.