*theres an extra life in an earlier spot in the library, refer to Sashamorning’s guide*
Just collect 9 lives and it doesn't need to be in one game.
It carries over even when you get game over and the tracker works :)
You get your first live (serum soda) in the cave area which can be seen in my video @ 2:35
For a quick run though (4 mins) check out my video:
100% Achievement Walkthrough: