For an Ashkenazi outside Israel, there is no way that kitniyot are permissible on the eighth day of Pesach, this year falling on Shabbat.
A better question is for Israelis for whom Shabbat is no longer Pesach, could they have cooked kitniyot on yomtov for a Shabbat meal (assuming eruv tavshilin) ?
Some did, most did not.
As for erev pesach, kitniyot would be forbidden to eat after the sof zman achilat chametz