My guess is that it would be pretty unlikely. I think it usually takes maybe 5 years or more for a polyp to become cancerous (though I am no expert, so may be completely wrong here), plus you have already had two findings on that previous colonoscopy that would be expected to cause rectal bleeding/blood in stool (the hemorrhoids and the diverticulitis) so it strikes me as more likely that it would either be a return of hemorrhoids or bleeding caused by the diverticulitis than that you would have developed a polyp that became cancerous in a pretty short period of time. 

I think only about 10% or less of positive FITs are cancer related anyway and given that you know you have two conditions likely to cause positive FITS, that you had a colonoscopy fairly recently that found no polyps likely to develop into cancer and that the FIT test isn't particularly high, I'd say the odds of cancer in your case are somewhat lower than the average.