Good evening, Moon,
Both sentences are correct, accurate, and natural. In (1), "opinion" is being used as a noncount noun; in (2), it is being used as a count noun.
The difference is in representation. In (1), opinion is conceptualized as abstract stuff; in (2), opinions are though of as a multiplicity of individuated things.
I personally would use "Opinion is divided" here. This preference of mind is reflected in COCA statistics for that phrase. The O.E.D. also has the phrase:
Quote:
1. d. Public or general opinion.
1598 J. Marston To Detraction sig. A3v True iudgement, slight regards Opinion.
1603 J. Florio tr. M. de Montaigne i. xl. 133 Opinion is a power-full, bold, and vnmeasurable party.
1638 R. Baker tr. J. L. G. de Balzac II. 96 It is not now onely that opinion governes the world; there hath beene disputing against Reason in all ages.
1753 J. Hanway II. xl. 259 Those..who offer incense to this..stupid idol, opinion.
1837 H. Martineau III. 7 The worship of Opinion is, at this day, the established religion of the United States.
1841 I. D'Israeli I. Pref. p. vi Authors are the creators or the creatures of opinion.
1871 ‘G. Eliot’ (1872) I. vi. 88 There is no part of the county where opinion is narrower than it is here.
1910 I. 429/2 Opinion is divided between Darius Hystaspes and Xerxes.
1946 W. Ivins iv. 74 Opinion about such a matter could in the most literal, faggot, sense become a burning question.
1996 May 63/1 Opinion is divided straight down the gender lines over whether Frank is right to indulge in a spot of extra-marital.
2002 (Nexis) 11 Nov. 3 Opinion is divided on what caused an increase in unemployment during the last economic quarter.