OS: Ubuntu 14.04 LTS
Java: Oracle JDK 1.8
Spigot Version Output:

[09:48:17] [Server thread/INFO]: This server is running CraftBukkit version git-Spigot-cce4667-ff617f7 (MC: 1.9) (Implementing API version 1.9-R0.1-SNAPSHOT)

Same problem for me, no sound, no blocking, no bouncing of entities that melee attack. (1.9.2)

No change with 1.9.2, git-Spigot-1480adb-8b61cc5

Can confirm iPyronic's info. This is much better though. All it's really missing is the proper effects/reactions.

I saw md__5 say it may not be worth fixing till 1.9.1, which I understand. Should you need to know what's still wrong with it:

• There's no shield block sound effect when the shield blocks an attack, projectile or melee (ITEM_SHIELD_BLOCK)
• When the player blocks a melee attack, the player flashes red, gets knocked back, and plays the hurt sound. They should get knocked back and have the shield sound play, but should not flash red or play the hurt sound (though they should still take the damage).

If the sound effect was added to projectile hits, they'd be working like vanilla. Melee would need a little more work. Either way, they're both fine for now, the issues are purely cosmetic. The player damage, shield durability, and knockbacks are occuring when they should, just not the resultant sounds and animations.

Tested on git-Spigot-f04e043-616a968 (currently the latest at this moment):

• The blocking sound doesn't play for me (neither melee nor projectile blocking plays the sound).
• Melee damage makes you flash red as if you hadn't guarded and it plays the regular hurt sound.

Shield durability is decreasing for both melee and projectile blocks and the damage looks to be correct as well.

.

As mentioned above:

skeleton (arrow) attack:

• shield doesn't play block sound
• shield doesn't show block animation
• shield doesn't decrease its durability

zombie (melee) attack:

• shield plays wrong sound

tested on CraftBukkit version git-Bukkit-52c7fc0 (MC: 1.9) (Implementing API version 1.9-R0.1-SNAPSHOT)

Agreed. Was trying to earlier and couldn't figure out how.

This needs to be re-opened, shields still aren't working entirely properly in vanilla Spigot. I tested without any plugins installed; the current behavior is that arrows hit shields and bounce off, but play no sound effect and don't damage the shield at all. They are supposed to damage the shield just like melee attacks do, and play a shield hit sound effect. Go ahead and test it out against a skeleton on a vanilla server and a Spigot server and you can see the difference. They're very overpowered against skeletons now in Spigot since they take no damage.

Related thread in forums: https://www.spigotmc.org/threads/mc-shields-added-in-1-9-not-preventing-damage.132341/