Translation:This accident has been reported to the police.
Indonesian and English aren't one-to-one like that when dealing with tense and aspect. "Sudah" literally means "already", so "has (already) been reported" does carry that meaning better, but "sudah" also just explicitly places things in the past when you don't have a specific time to provide, so "was reported" works too.
Yeah, /kepada/ should be acceptable. In fact, I've been taught it's the better choice because /polisi/ are people and that /kepada/ is supposed to be used with people rather than using /pada/ because of the animacy hierarchy of the language.
[Edit:] Is /ke/ used here just because this is "bahasa sehari-hari", or is there a specific meaning encoded into /ke/ whereby (and I'm speculating because I don't know) somebody would use /ke/ for /Dinas Polisi/ but never use /kepada/ with /Dinas Polisi/ as an object in bahasa formal?