Most IV crush will be instantaneous upon open, given the fact that the uncertainty of earnings is gone. Translation: we know the stock (probably) won't move 10% this week.
If there is IV crush and sustained drop today and tomorrow it might be a good move to buy calls tomorrow evening, with the intention of selling them within the next couple of weeks.
I won't do this however. That strategy has burned me too many times in the past. Most sure fire way to pull it off is to invest in long dated options (+6months), not too far OTM (max $900), but I'll just use the capital required for that to sell BPS against.
Not advice, just my way of thinking nowadays.