If an effect grants power by killing a unit (like Malzahar), can Soraka save the unit and the player still gain the power? Does Soraka also prevent effects that directly say 'kill a unit'?

Ruling: Yes to both. When an effect grants power by killing a unit, you can use Soraka to save the unit and still gain the power. Soraka also prevents effects that directly say "kill a unit."

Nuances:

• The power gain from kill effects resolves even if the unit is saved by Soraka
• Soraka can prevent direct kill effects on units