The judicial power of the United States, shall be vested in one Supreme Court, and in such inferior courts as the Congress may from time to time ordain and establish.
The Constitution did not create the Judicial Branch; it instructed the Legislature to do so. The Legislature created the Judicial Branch with the Judiciary Act of 1789.
Art. 3, Sec. 2:
In all cases affecting ambassadors, other public ministers and consuls, and those in which a state shall be party, the Supreme Court shall have original jurisdiction. In all the other cases before mentioned, the Supreme Court shall have appellate jurisdiction, both as to law and fact, with such exceptions, and under such regulations as the Congress shall make.
The Constitution states explicitly that the Congress does have regulatory authority over the Judicial Branch.
The Congress can do away with the Circuit Courts and District Courts. The Legislature can do away with all but one justice, or authorize however many it chooses. There have been as few as 5 and as many as 10. The number currently stands at 9.
The number was raised from 9 to 10 after Lincoln got a big scare in the Prize Cases, with his war effort surviving by a 5-4 vote. With 10 justices, 4 appointed by Lincoln, he was secure for the remainder of the war. After Democrat Andrew Johnson became President, the number was lowered to 7 by attrition, assuring that Johnson would never nominate a justice. After Republican Grant assumed office, the number was restored to 9, allowing Grant to fill vacancies. There it has remained since.
The vast majority of cases at the Supreme Court are on Appellate jurisdiction. The Congress can remove the Appellate jurisdiction to hear any or all such cases. In cases of original jurisdiction, the Supreme Court acts as a trial court. That almost never happens.
The Congress controls the funding of the Judicial Branch as well as of the Executive Branch.
All of which has zip to do with the notion of Congress imposing a code of ethics.