Approximately 51.43%
Gary has 5 hours of free time per day, which is equivalent to 35 hours of free time per week (since there are 7 days in a week).
The total time Gary spends on the Internet and playing video games per week is 9 + 9 = 18 hours.
To find the percentage of his free time spent on these activities, we divide the total time spent on them by the total free time available, then multiply by 100:
(18 / 35) x 100 = 51.43%
So approximately 51.43% of Gary's free time is spent on the Internet and playing video games.