The internet is a massive trust game of sorts. Itch has no responsibility if there are a couple of devs uploading malware to their platform. However if they do nothing about it then they are.
My advice? Use a antivirus software. They tend to be accurate whether or not there is a malware. Avast, Kaspersky and many other well known ones will do the job.
If you wish to be additionally safe at the cost of time? Look at user reports and or search the developer on massive public forums/sites. What I tend to do is see if the people actually enjoy the game to begin with by reading the comment section.
But rest assured this developer and many other popular developers are trusted