Yes, 9/4 is in simplest form.
To determine if a fraction is in simplest form, we need to check if the numerator (9) and the denominator (4) have any common factors other than 1. The number 9 can be factored into 3 x 3, and the number 4 can be factored into 2 x 2. Since there are no common factors between 9 and 4, the fraction cannot be simplified any further. Thus, 9/4 is already in its simplest form.