Answer:
[tex]\$18[/tex]
Step-by-step explanation:
Convert milliliters to liters using the conversion [tex]1,000\:\mathrm{ml}=1\:\mathrm{l}[/tex]:
[tex]9,000\text{ ml}=9\text{ l}[/tex].
Since the grocery store sells soda for $2 per liter, Pablo needs [tex]9\cdot \$2=\boxed{\$18}[/tex] to buy the soda.