Translation:It is not nine o'clock now.
Yeah, we were taught in elementary you should always write the number out fully when it is fewer than one hundred.
"It's not now 9 o'clock" isn't the most common response in English, but it is still a proper format (if a little archaic). This lesson marks it as incorrect for the placement of "now".
If we were to include the word "now" at the end of the sentence in American English, it would almost unanimously include the word "right": "It is not 9 o'clock right now."
This is because the word "now" by itself is superfluous at the end. By saying "it is", you've already marked the tense as present. "Right now" indicates precision in the timing, which is what this translation is going for.
Placing "now" earlier in the sentence structure as above adds importance to the word, indicating that same greater precision.
I feel like there's a slight connotation between the 2.
If told "you can only purchase the tickets at discounted price while the clocks reads 9 o'clock" and your friend was impatient you'd say "it's not 9 o'clock right now" because it's too early and the timing must be precise. On the other hand, if you were buying tickets like crazy and were questioned why you stopped at 9:01 you might reply with "it's not 9:00 now" using the now as an "anymore" indicating that the importance of the precision has passed.
Also "I need an aspirin right now" implies the headache is unbearable. But if someone was being annoying you might, after one of his shenanigans, say "I need an aspirin now". Meaning you just started to get a headache.
"I need $100 right now" is important as the money is necessary immediately "I need $100 now" could be said if you have become indebted or foresee an expense. There's no rush, you need the $100 but not right now, just the need has appeared right now, but the resolution is not immediately necessary.
"You need to tell the truth right now" - because I've had enough of your b.s. and my patience is gone. You're probably already in trouble.
"You need to tell the truth now" - it's important to start telling the truth, but there's no implication of repercussions.
I think that's what the "今," at the beginning and the "今" at the end are implying. There's different connotations to its placement just as there's different connotations when adding "right" to "now".
I think you meant "It's now not sth sth" which would be correct placement. But not in the case of telling the time, "It's now not 9 o'clock" or "it's not now 9 o'clock" isn't how we write in English.
The first one doesn't require the word now in it as the time stated along with it does the job.
The second one is patching "it's now not" as a comment on a previous statement, up with the way we write when telling the time, which is wrong.
I am an utter amateur, but as far as I can tell, you can treat it as a specific particle to precede a negation. は is here something like "is" where では appears to be more like "is not", but must be followed by the rest of the negation, ありません。Redundant, but necessary for proper/polite grammar?
は is a marker that indicates the topic of the sentence, and では acts as its negative counterpart. The ありません bit is actually the negative form of あります which means "exists" or "is" depending on context. は isn't a copula - remember that japanese sentences always end with the verb.
9 can be pronounced either く or きゅう (or ここの) depending on the context it's used in. For example, when you use 9 for the hour, it's く, but when you use it for minutes, it's きゅう.
It's 9:00 = 九時です = くじです
It's 9:09 = 九時九分です = くじきゅうふんです
(ここの is the kun'yomi reading, or the native Japanese one. It's used, for example, with the generic counter つ. So 九つ = ここのつ = nine [things])