We will be there at the same time.

Mid-September is our favorite time of year to visit. This year we're staying at the DLH for the first time.
Here is my plan. I do not make breakfast reservations. We will either eat in our room (I get groceries delivered from Von's) or we will pick something up in Downtown Disney. My children get up EARLY though and like to much as they watch the Disney Channel and wait for Disneyland to open.
For lunch we do a sit-down meal and I make a priority seating reservation. This will either be a character meal or at a place like Carnation Cafe--we LOVE Carnation Cafe and likely will eat here at least twice. You don't have to have reservations (in mid-September) for places like Carnation Cafe, but the reservation allows you to jump the line of people waiting for spots and will help you get a spot in the shade as (currently) Carnation Cafe is outdoor seating.
Sometimes our lunch reservation technically is a "late breakfast" according to the Disney folks--such as the Minnie and Friends Breakfast, but we treat it as a lunch since we eat breakfast pretty early. It works great for us!
We typically eat dinner outside the park. On our last trip I did not make any reservations at places like Rainforest Cafe or ESPN Zone and when we tried to just "drop-by" with hungry children in tow, they all had 45-75 minute waits. That didn't work for us at all! This year I will be planning ahead, even if it is something as basic as having their numbers with me in the park and calling them in the afternoon to see about reservations.
A quick serve place we like (no reservations) is Whitewater Snacks in the Grand Californian and we'll definitely be utilizing them again this year. I wish they were in the Disneyland Hotel as I know we would use them even more! Still, we're going to take advantage of the dedicated entrance into California Adventure and use them a few times this year.
I hope this information helps. Don't feel that you need to make three reservations a day, but my suggestion is to go in with some sort of a plan. For our family, I know that my children need to be able to sit down in shade (preferably air-conditioning) at least once a day--so I plan and make reservations accordingly.