Partially. The R9s lacks Band 12 and Band 17 (700MHz). You will get 3G/H+ on T-Mobile and AT&T, but 4G LTE will be spotty. This is a hardware limitation, not software.
You will need:
Disclaimer: This article is for educational purposes. The author is not responsible for bricked devices. Always verify your model number before proceeding. oppo r9s global firmware
Avoid "Auto ROM Installer" apps on the Play Store. They are often malware. Partially
Flashing CPH1607 firmware onto a CPH1610 will result in a black screen (touch failure) because the display drivers are mismatched. oppo r9s global firmware