In Science we are putting vinegar and baking soda into a test tube and putting a cork in it so that it will fly off. How much vinegar and baking soda would I need for the cork to go 8-9 meters.

The answer depends on the concentration of your vinegar. You ideally need to match the amounts of soda and vinegar for the most gas.

So measure out a known amount of soda. Then measure an amount of vinegar and add it a bit at a time until the mixture no longer fizzes. See how much vinegar you used and use that ratio in your experiment.

If you want really concentrated acid then try to get "glacial acetic acid"