Final answer:
The statement is false; U.S. state criminal courts typically require a unanimous jury verdict for a conviction.
Step-by-step explanation:
The statement that only 9 of the 12 jurors need to agree on a guilty verdict for a conviction in state criminal courts is false. The U.S. legal system typically requires unanimity in jury verdicts for criminal trials. According to the unanimity rule, all jurors must agree to either convict or acquit the defendant. If the jury cannot reach a unanimous decision, this often results in a mistrial.
Moreover, the U.S. Supreme Court has upheld the necessity of a unanimous verdict in federal criminal cases through the Sixth Amendment, and most states follow suit for state trials.