The Ninth Schedule to the Indian Constitution was added by

The Ninth Schedule (and Article 31B) was introduced by the Constitution (First Amendment) Act, 1951 to protect certain laws—initially land-reform and abolition of zamindari measures—from judicial review by saving them from challenge under Fundamental Rights. Contemporary sources state explicitly that the First Amendment added the Ninth Schedule to shield a set of statutes (initially 13) intended to implement land reforms and related measures [2]. This constitutional change was a direct parliamentary response to judicial decisions striking down legislation seen as infringing property-related fundamental rights, and it remains the established origin of the Ninth Schedule in 1951.

Sources

1. [1] Indian Polity, M. Laxmikanth(7th ed.) > Chapter 92: World Constitutions > APPENDIX IV Constitutional Amendments at a Glance > p. 716
2. [2] Indian Polity, M. Laxmikanth(7th ed.) > Chapter 27: Judicial Review > JUDICIAL REVIEW OF THE NINTH SCHEDULE > p. 299