verb agreement - "Office hours" - group or collective or compound noun vs. plural

I wrote,

"Is there office hours Thursday at 9am?"

I know the hours are plural but I feel it's a collective noun. "Office" is a noun adjunct making the meaning of "hours" more like a meeting or offering so I went singular. It feels awkward but "are" feels even more awkward.

So... Is or are?? Is "office hours" plural or singular in the educational context?

Update 1: My wife asserts is the same as pants. I replied that taking office out of the sentence would change the meaning of the sentence completely. "Is there hours Thursday at 9am?" That got me thinking that office hours may be more of a compound noun like toothpaste. Compound nouns can have a space between them e.g. bus stop.

The second part that I think is throwing me is the "at 9am". Can hours be at 9am? That's just silly, but office hours can be at 9am.

Update 2: I would have to agree with @BillJ on this one and that it's not a compound but rather the original noun-adjunct "office". Additionally, I did not include the context. In the US, professors have a time of day when they make themselves available to students. It is an open meeting. I apologize because as this might look like "hours of operation" for most people which would indeed make the entire question seem frivolous. Conceptually I was asking, "Is there a meeting Thursday at 9am?". This continues with the existence part, a meeting can or cannot exist.

Ultimately, my wife is right. While I may think "office hours" as an offering or an open meeting, it derives from a business office having hours of operation. The pants were plural then (literally and figuratively) and the office hours are now.