I think that Iran accidently hitting the passenger plane actually stopped a full blown war from kicking off.
I think they would have had further attacks planned, both overt and through proxies, but the minute they hit that plane, even though they tried to hide it, they knew that there would be massive backlash and loss of support internationally if they did anything further.
I also think that the White House knew this early, not straight away, but before the msm, and that's why they are coming out with these statements: they know Iran want the heat to die down and so won't respond.