I don't think the Doctor is much impressed on Iniss or the Yeerks. They sound like the sort of species he doesn't much care for and the kind he might interfere with if he'd stumbled across them. It would be one thing if the hosts were willing and not under duress but from what Tom's told him, it's nothing like that. So basically the Doctor probably wouldn't be terribly friendly with Iniss, at least from that impression.