I finally got my friggin iBook G3 from 2001, and I installed Mac OS 9.2.2 onto it. It was on Tiger and it was killing me how slow it was, and now it flies.
I run Tiger on a G3 much slower than your iBook and it flies. Replacing the clapped out HDD with an SSD undeniably helped but so did using every tweak and optimisation available.
And the battery works again, lol.
It was only like 19 quid from Ebay, listed as "untested". Took a chance, and am happy so far.
Congrats on both counts.