I dont really think we should be worried.
What happened with Mighty Number 9 was that the developers set unrealistic goals from the start, wich was already a red flag to consider before even backing up the project, they as far as I am aware werent very open abotu the development process either, now compare that to titles like TFH where the goals were very realistic from the start, plus they had already shown footage of the in progress game even before the crowdfunding was finished, another example being BloodStained wich recently got a playable beta as well.
Sure, there are several projects that fail or are plain hoaxes wehn crowdfunding, but I am certain that TFH is not one of those, It is a pretty solid project, with great people working towards it, they have truly been very transparent with the process by keeping us updated and showing livestreams of their progress, something not many devs will do, plus with the prior game they had developed wich unfortunately got cancelled (Thanks The Toy Company) being a rather solid game even in its unfinished status, I am certain we are in good hands.
IS it okay to be skeptical, sure it is, however I am confident on this team, if I wasn't I would of not put my money on the line.