I currently live in Eretz Yisroel and I plan on being in the U.S. for Pesach. I’m wondering if I can sell my chometz there because Pesach starts a few hours earlier in EY. (also don’t think I could sell in EY because yom tov ends later in US).
You should ideally sell your chametz in Eretz Yisrael so that your chametz in E.Y. is sold by the time the prohibition of chametz begins there, even though you will be in the U.S.. With regards to the end of Pesach, even Rabbanim in E.Y. use one of a number of methods to assure you will not re acquire your chametz until after Pesach in the U.S.. By stipulating that they are not acquiring the chametz of someone abroad or by acquiring the chametz in to their own possession and then after Pesach in the U.S. they transfer ownership to you. In any event no agent can purchase chametz on your behalf while it is still pesach for you, as an agent can not perform a legal action that is for your detriment without your express directive.
Chametz in a Different Country
An interesting question arises when a person owns chametz in a location different from his current residence. Does the latest time of selling chametz follow the place of the seller’s residence, or the location of the chametz? Authorities dispute this question. The consensus among the poskim is that the timing depends on the location of the seller. In light of this ruling, chametz must therefore be sold before the prohibition of chametz commences in the place where the seller is (See Oneg Yom Tov 36; Ha’elef Lecha Shlomo 206; Iggros Moshe, Orach Chaim 94-5).
According to this ruling, if a person from outside Israel is present in Israel for Pesach, he must ensure that the chametz he left behind is sold before chametz becomes prohibited in Israel (assuming that this is the earlier of the two times). If his family (who are still home) continues to use the chametz in his absence until the time of prohibition, he should ensure that the chametz is transferred to their possession, so that they will be able to sell it according to local time (Minchas Yitzchak 7:25, Sec. 1).
Due to dissenting opinions among authorities, the same rule should be applied in the other direction. If somebody from Israel is abroad over Pesach, it is preferable that he sell his chametz (which he left at home) according to the earlier time of Israel, and not wait for the later time of chutz la’aretz.
With regards to buying back after Pesach, it should be verified, but generally the Rav will arrange that those abroad will not re acquire until after their Pesach as mentioned above. See Mikraei Kodesh Vol. 1 Pesach Siman 76, Shevet Halevi 6:243, Sefer Mechiras Chametz Khichaso pg. 140 – 141.