welcome to the community! you might check out my thread I made and maybe ask questions there too. maybe you find something there what’s in your interest? https://community.wanikani.com/t/new-recruits-of-november/46891?u=qozm
I’d recommend learning the grammar stuff - at least learn the basic “particles”, because it will turn out to be very very beneficial for both Wanikani and learning the Japanese language - you would miss out the additional opportunities on things getting stuck into your brain, when you only do WaniKani while not knowing much of the language itself.
don’t get to hasty though, even if WaniKani really makes fun. there will be review shortages when you have to wait for the last Kanji reviews before reaching the next level anyway so there’s enough room for the language or of course to contribute to this fantastic forum.
you should also check out userscripts, which make the WaniKani Experience even wanikanier: The New And Improved List Of API and Third Party Apps