I love DCA but I think in 10 plus trips to DL, have only gotten there at opening once! And that was on a departure day when I just really wanted to ride TOT, Soarin and CA Screamin and needed to make sure I got there right on time.
I go to DCA most every day of my trip, but generally get all I need to do done over the course of that with getting there late morning. I really like to have lunch over there so generally arrive to coincide with that (get there, fp Soarin or Screamin, have lunch, then go from there).
Of course, if you get to DL very early (can be 7:00 on an EE day), you may very well be ready to get over to DCA when it opens at 9:00 or 10:00. I would just wait and see how your time goes, just know that unlike DL, you don't have to arrive at opening to make it all happen. I do recommend you fastpass Soarin first, its generally the one that has fastpasses run out first or have them with the latest return times.