Must admit I can't see if the ground spoilers have deployed immediately on touchdown. Haven't got my (early) A310 course notes to hand, but I presume automatic deployment is signalled by main-wheel spin-up? The latter, of course, may not happen on a flooded surface, and the touchdown seems to be fairly gentle: a firm touchdown is desirable on a wet surface. Lack of main-wheel spin-up due to aquaplaning, as safelife points out, would be a double-whammy: no braking capability and no ground spoilers. (Ground spoilers dump the residual lift of the wing, as well as providing valuable drag in the early stages of the landing run.)
Not sure at what point in the landing run Airbubba can see the ground spoilers, but I think their second-line deployment signal comes from the pilot selection of reverse idle. That may have been done immediately after touchdown, but I can't tell from the video. (Can someone current tell us if reverse selection also requires main-wheel spin-up? If that were the case, it could explain why full reverse was not achieved until the a/c is abeam the camera.)
Re use of autobrake, the MAX selection is only used for rejected take-offs in my experience. On the A320, MED (medium) is standard for landing on wet or contaminated runways, and I think the same would apply to the A310. It goes without saying that brakes are useless until the wheels spin up.