Not a fan of the way it currently works. To get a weapon to +9, you also have to craft 6, 7, & 8 (Since all weapons start at 5).
Text from the +9 shard:
This mirror-like shard is imbued with great magical potential and can be used to increase the maximum enchantment level of a crafted item from +8 to +9, the crafted item will then be able to hold effects totaling +6 in value.