What was significant in having the approval of nine states, rather than all 13, to bring the Constitution into being?

A unanimous vote of the states was necessary to change the Articles of Confederation.

Explanation:

Ratification is the official way to confirm something, usually by vote. It is the formal validation of a proposed law.

The ratification process started when the Congress turned the Constitution over to the state legislatures for consideration through specially elected state conventions of the people.

As dictated by Article VII, the document would not become binding until it was ratified by nine of the 13 states.