Blizzard stresses that if you believe you are potentially going to get the Season 9 PVP rewards for being in the highest percentile of winners and think you might be eligible for the arena titles or Vicious Gladiator's Twilight Drake, you should refrain from transferring your character to a new server while the reward tabulation is going on. If you're a big PVPer, stay on your server until the winners have been announced.
PVP Season 10 will begin approximately one week after Season 9 ends. All honor over the 4,000-point cap will be turned into gold at 35 silver per honor point.
Blizzard's full post after the break.