hello dear,

YES!!!! Ews reservation is applicable for TS CET. 
The main purpose of issuing this certificate by the government is to give the benefits of reservation to the people of the weaker sections of the general caste. 
The reservation for EWS category is 10%.
If you belong to general merit, you can compete only in 40.50% seats as 59.50 seats are reserved.
If you are an ST, you can compete in 48% seats (7.5% reservation quota seats+ 40.5% merit seats).
On the same lines, SC category candidates can compete in 55.5% seats (15% reservation quota seats+ 40.5% merit seats) while OBC category candidates can target67.5% seats (27 % reservation quota seats+ 40.5% merit seats).

I hope this would help you.