This is a list of known period-9 sparkers. Period 9 requires a great deal of luck with direct search programs such as JLS and WLS. 104P9 was found this way, but most are either semi-natural or were found with dr, which doesn't search for specific periods.
48P9. Both the vertical domino and the actual dot can be used as a dot, and the vertical domino can occasionally be used as a domino. Note that the actual dot is doubly delayed. Clearance is not that good. (click above to open LifeViewer) RLE:herePlaintext:here
Snacker. This particular LifeViewer window shows how extending it can increase clearance as well as the alternative stabilisation that increases side clearance; the smallest form only has one copy of the active region. (click above to open LifeViewer) RLE:herePlaintext:here
50P9. Make sure the active region has receded in generations 3 and 4. Usually less powerful than 104P9, but the lack of heavyweight side sparks can be an advantage, as well as its greater side clearance. (click above to open LifeViewer) RLE:herePlaintext:here
84P9. The domino isn't as far forward, but it has a different profile on the side from 50P9, and the problematic generation is generation 4, not generation 3. (click above to open LifeViewer) RLE:herePlaintext:here