I did my belt and tensioner on my CL9 a while back - sourced OEM parts through oemacuraparts.com.

Belt was ~$35, Tensioner ~$90, shipping was ~$50. Couldn't be bothered doing it myself so got the local mechanic to swap it over - 1 hour labour at $80. Whole exercise only cost ~$255, which I recall was less than what Honda was asking for the tensioner alone!