Commissioning is far more important than Advanced Camp graduation.
However if you can afford to go to AC, then go. Your DS will appreciate seeing you after a challenging month.
I would however recommend skipping the buffet dinner at the Ft. Knox Sabre and Quill and instead get your son off base to a restaurant nearby. The dinner buffet is not anything special (no ceremony) and your DS will greatly enjoy getting away from the post. The BBQ at Colton's Steakhouse in Radcliffe was not bad and close by. A nice thing to do is to have your DS invite one or two cadets whose parents couldn't come, and treat them to dinner. There are rules about keeping your cadet close to Ft. Knox, so a trip to Louisville for dinner is not recommended.
There is much to see in nearby Louisville and Fort Knox itself is interesting. There's University of Louisville, good dining, and especially fun were the tours of the Bourbon distilleries. We toured Old Forrester and it was a fascinating visit. If you like baseball, a trip to the Louisville Slugger museum is a must see. A terrific place for breakfast in Louisville is Wagner's Pharmacy across the street from Churchill Downs. This is a historical place for seeing Kentucky Derby history and also fried bologna sandwiches! The Frazier Kentucky History Museum has a great exhibit on Lewis and Clark. If you find this part of history of interest, their installation is really amazing and worth a trip.
A cheap but ageing place to stay is the Gold Vault Inn, which is a few minutes from the Main Gate. It was clean and friendly. They have a nice indoor pool and free breakfast. It ain't the Marriott, but it is very reasonable.
Something to keep in mind is that the main reason you should attend AC graduation, is to support your DS, not for the ceremony itself or the tourism. Keep your perspective and it will be well worth it.