You need 19 troops to obtain the 9th star and 24 for the 10th… From the spoilers, even at the beggining of next February, none kingdom will be able to have the 9th star…
The main reason is a reduction of points after the 10+th troops (almost divide by 5). So you need between 4 and 5 new troops to increase your kingdom power level:
Something should be done either:
- remove the 10th troop formula tweak
- give points when challenges are done