Did they cross-rotate the non-drive axle? This can very often cause a radial pull and even more common if rotate intervals are too long, uneven (like here since you said 5k for the first time and 9k for the second), or the alignment hasn't been kept up. This is why I generally do not like to cross-rotate tires but then some customers get angry just the same that we didn't do it "exactly as the owner's manual states." Swap the rear tires side-to-side and see if that fixes your problem (and then swap the front tires also if the pull is still there). If that fixes it, just don't cross-rotate any more and you'll be fine. This isn't something you will be able to see looking at the tires. Even brand new tires can have a radial pull.
