I have a few tips for PvPing in 1.9:
1, Enchant your armor with Mending and get a few stacks of exp bottles. Use the exp bottles in case if your armor is damaged.
2, There is a bug where Arrows of Harming deals the same damage as a normal arrow, so use other types of tipped arrows.
3, Eat Chorus Fruits to get out of a combat, sometimes you may teleport through a wall or a floor. It is also useful to fill up our saturation so you can regen faster (this is the same with golden apples).
4, Use your axe against shields so you can disable the shield for a few seconds. But I think the shield is broken in Cubebuilders.
5, Flying with elytra reduces your hitbox. Also rapidly jumping while having the elytra on allows you to travel fast while reducing your hitbox.
Share your own strategies by commenting down below :) .