9 grams to teaspoons

From 1.5 to nearly 2 teaspoons. If it were 5g per teaspoon, 9g would be 1.8 teaspoons. 9g of salt per litre is an isotonic solution, same concentration as body fluids and the most common fluid replacement solutions.

The conversion is listed variably on the internet. 1 teaspoon = 5-6g depending on the source; probably it is different for different types of salt, which would vary the weight per volume slightly.