What is the roman numerial for 9?

Answer 1

9 is IX.

Roman numerals for 1 - 27:

I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, XIX, XX, XXI, XXII, XXIII, XXIV, XXV, XXVI, XXVII