It you know, "He's will spot dodge every time I do A," that's a free punish. It all depends on where you are and whether you're dashing or stationary. If you dash up ans suspect a spotdodge, a dash attack (earlier for Falco because his dodge is short) can be a free kill at 80-90. If you aren't as sure about the timing, just run up and sit in your shield, if you're comfortable enough with the grab timing, use that to punish. If not, use one of DDD's longer moves: F-tilt if you're far away and D-air or D-tilt if you're close up. All three of those moves are relatively quick (especially if you don't crouch the D-tilt) and last way longer than grabs.
Oh yeah, If you're in the air, and your afraid he's waiting to shield/spotdodge you B-air, B-reversed (so that you're boosted from the edge of your backair range into their face) inhale works wonders. I stole that move from Coney when I saw how well it worked in some of his sets. Also, some people get inpatient during the set and try to mash out of inhale, especially if you use it a lot (successfully). You know what to do when this happens. ( =