When Isru Chag Pesach for Israelis falls out on Shabbat – is there any practical room to say that on that Shabbat one may use his chametz that was sold to a non-Jew? Someone sent me that Hacham Ovadiah allowed this in Yehave Daat 2 Siman 64, and Yabia Omer Orach Chaim 9 Siman 46. I am confused – how can the Jew buy it back or make a kinyan on Shabbat to allow this? Is this only theoretical? Can you help?
As you correctly note, Rav Ovadyah is lenient in this matter.
His main debate is concerning the matter of muktzeh, but he adds that concerning the problem of making a kinyan from a non-Jew, a clause is included in the deed of sale that permits the Jewish owner to eat the chametz on the Shabbat following Pesach.
For sales of chametz that don’t include this clause, the chametz (which still belongs to a non-Jew) cannot be eaten on the Shabbat following Pesach.
Please see here, and the comments beneath the answer, for further details.