He wasn't but I also noticed and from highlights Gomis was wearing #9. Gomis wore 18 when Giovinco played. I think (completely guessing here) being an Arab Cup game (not league game) maybe rosters are finalized earlier in the competition, therefore Gio was ineligible? Maybe also that's why Gomis was wearing 9? Did he switch and give that number to Gio earlier in the season?
Complete guesses and questions on my part. Don't really know where to look for Saudi soccer info.