Wouldn't put it past the Biden team to provide intelligence, targeting information, and technical assistance to assure an Iranian attack on Israel.
I am not certain the US will actively attack Israel since that might be a bridge too far for many American friends of Israel. But, sharing intelligence with Iran is not farfetched, although I would be surprised if Israel gives the US a heads up on when the fight will begin. I imagine there is little trust by the Israeli military and intelligence agencies for their counterparts in the US military and the CIA. If hostilities do start, the US will urge the parties to negotiate all while refusing to provide military assistance to Israel or its’ allies. If the war seems to be going in Israel’s favor, the US will demand the UN intervene to prevent an Israeli victory.