Droning is a form of indirect involvement. Look for it, you'll find it. They are planning direct involvement shortly.
If it happens it happens. But that is completely against Obama's Middle Eastern Policy for all of his Presidency. Which is to work to end the war, not send more troops out there, and to try to rebuild. And even if it was War, from what I have read Mosul itself would be a 6 Month+ operation, and that would basically relegitimize the Iraqi Government to an extent, as long as they didn't fall back in to Sunni/Shia stuff in Government. But after that there is still all of Syria, and Syria isn't even really being focused on right now.
Because ISIS started as (AQI) Al Qeada in Iraq, they are trying to work on Iraq first. The American people said they didn't want to get involved in Syria, so they stayed out of Syria, and now they are trying to get a Cease Fire in Syria, not start firing more.
I'll look, but I really don't think that Obama would just flip like that, when there is no way he could get it done in the time he has anyway. It would be a complete reversal of his positions that he has held on strong to for his entire presidency, and without the bonus of getting to say you won a war before you left office as a historical point.