You can use a distribution from a Rollover IRA in 2018 to pay off your credit card, however, the higher education expenses paid in 2017 will not be applicable as an exception to an early-distribution on this 2018 IRA distribution.  Only qualified higher education expenses paid in 2018 will be applicable as an exception to the penalty.  Paying the expenses in 2017 by credit card then paying the credit card bill in 2018 does not turn a 2017 expense into a 2018 expense.

On the other hand, if the tuition is being paid in 2018, this will be an expense paid in 2018 and can be applied to a 2018 IRA distribution to reduce or eliminate the early-distribution penalty.