How to Convert Sucrose to Glucose and Fructose
Sounds like a great experiment! 

As you state, a sucrose solution in water eventually hydrolyzes to fructose and glucose, but without a catalyst, the reaction rate is extremely slow; beverages are stable at room temperature for years. However it is hydrolyzed in hours at room temperature by adding sucrase enzyme (secreted in the small intestine), invertase enzyme (derived from yeast) or even a weak acid such as citric acid, tartaric acid, or even dilute hydrochloric acid. 

You may need to test whichever of these are available for compatibility with Benedict's solution, though, and you may need to test some of the other ingredients in the drinks to see if they also cause false positive otr negative effects. You might compare the results from the Benedict's test with those from a blood-sugar glucometer (the solutions may need to be diluted in both tests to stay within a measurable range).

BTW, study of yeast fermentation of sucrose is responsible for the name enzyme, meaning leavened with yeast, so one could say invertase is the epitome of an enzyme.

Please share your experimental results here.