PCB with KiCAD: Possible error in routing decoupling capacitors
Decoupling caps should be physically close to the chips they decouple.  Like, right next to them.
KiCad doesn't have the smartest autorouter.
Consider laying out the power traces by hand before letting the autorouter have its fun.
KiCad will let you establish net classes; this, in turn, will let you define the traces on 5V to be thicker.
Something about the way KiCad is set up, or what you're doing, is making it route a trace and then pour the planes.  That's cutting up your 5V plane.  It's been a while, but I think you can pour the planes first, and then autoroute, and then recalculate the planes (but that may be Eagle -- it's been a while).