Sept 17 (Reuters) - Telehealth company American Well Corp’s shares rose 42% in their debut on the New York Stock Exchange on Thursday, after the company raised $742 million in its initial public offering. The stock opened at $25.52 compared with the IPO price of $18. Reporting by Abhishek Manikandan in Bengaluru; Additional reporting by Madhvi Pokhriyal; Editing by Maju Samuel and Shinjini Ganguli