Is there sufficient evidence to confirm additional Planet in solar system
This question already has muliple answers on this site... 

However : Yes, astronomers DO have enough data to speculate about a possible Ninth Planet. 

The orbits of six KBO are correlated, and a possible ninth planet could be the reason for those peculiar orbits. See image below for the computed results of the possible orbit of the ninth planet.: 



However, since the Planet has not yet been SEEN or DETECTED, its existence is only supposed. We have nothing to prove it really exists. But if it exists, we know where it is :p