If your main reason for dining at La Hacienda is to see IllumiNations from your table, I would not keep the reservation. La Hacienda has some tables with a good view, some with an okay view and some with no view at all. While you can ask for a table with a view when you check in, often La Hacienda will not take requests and you will have to accept the next available table for the size of your group. Also, by 7:45 most seated at tables with a good view will probably not leave until after the fireworks.
If you decide to keep the reservation you could try eating quickly, then try to find a spot around the lagoon, although that might be hard with 9 people. There is no outside viewing area for La Hacienda diners.
If you can find a later reservation at Rose & Crown it has patio tables and if you are seated inside, there is a viewing area adjacent to the patio for those who are dining at R&C during IllumiNations. Servers will pace your meal accordingly if you let them know you want to go outside to view the show.
