Hi, I have used a hotel babysitter before but we had a 2 bedroom appt so my daughter (& on the next occasion my son aswell) could sleep in the bedroom & the sitter could watch TV in the lounge. Going through an agency I would feel comfortable but its different for everybody. I've always been pretty leanient (I guess thats the word)with my kids, happy to have them babysat & even sleepover at families houses etc from a young age where as alot of people wouldnt be comfortable with that IYKWIM.
At least ud only be down stais so can check on ur son as often as u like
Good luck