Is my cat sick or what is he trying to tell me?

One of my cats mostly poops outside the litter box, like almost anywhere in the house. Sometimes theirs blood in it, but most of the time there isnt. We did take my cat to the vet for their shots like in april and their about 8 months old now. the first time my cat is okay, then the next time, he had an ear infection but everything else okay so they gave us some ear drops to put in his ear. After that he seemed okay until like now he starts pooping outside litter boxes, and blood in his poop again. I asked about the blood in the poop before but people said "it'll go away." or "take them to the vet". Idk is he trying to tell me something like hes sick or something?