You can read the decision here. It's a short statement that the expedited petition for certiorari is denied. That means that the petition itself could be accepted at a later date--presumably with Justice Amy participating. She didn't participate today because she didn't have time to read the briefs:
The motion to expedite consideration of the petition for a writ of certiorari is denied. JUSTICE BARRETT took no part in the consideration or decision of this motion.
Justice Alito--joined by Thomas, and Gorsuch--made it pretty clear that they were unhappy with Roberts' hijacking of this case, by issuing a "statement." Kavanaugh didn't join the statement.
Statement of JUSTICE ALITO, with whom JUSTICE THOMAS and JUSTICE GORSUCH join.
The Court’s handling of the important constitutional issue raised by this matter has needlessly created conditions that could lead to serious post-election problems. The Supreme Court of Pennsylvania has issued a decree that squarely alters an important statutory provision enacted by the Pennsylvania Legislature pursuant to its authority under the Constitution of the United States to make rules governing the conduct of elections for federal office.
It would be highly desirable to issue a ruling on the constitutionality of the State Supreme Court’s decision before the election. That question has national importance, and there is a strong likelihood that the State Supreme Court decision violates the Federal Constitution. The provisions of the Federal Constitution conferring on state legislatures, not state courts, the authority to make rules governing federal elections would be meaningless if a state court could override the rules adopted by the legislature simply by claiming that a state constitutional provision gave the courts the authority to make whatever rules it thought appropriate for the conduct of a fair election.
That does not mean, however, that the state court decision must escape our review. Although the Court denies the motion to expedite, the petition for certiorari remains before us, and if it is granted, the case can then be decided under a shortened schedule. In addition, the Court’s denial of the motion to expedite is not a denial of a request for this Court to order that ballots received after election day be segregated ...
And, in fact, those ballots are being segregated. Justice Amy will have a chance to participate in deciding whether to accept the petition on a non-expedited basis.
Maybe it's just me, but it appears to me that Roberts is sacrificing good will in a shortsighted manner with this behavior.