In the casual situations, I would say like 九点十五, 九点零四， 八点二十， 四点半， 三点四十，两点（整）。

九点一刻 or 九点三刻 sounds a little bit formal than 九点十五 or 九点四十五.

分 is omitted most of time and 九点十五分 sounds a bit formal, for you are trying to be accurate.

But if you add 秒, you should not omit anything, like 九点十五分三十六秒, not 九点十五 三十六.

As for 'a quarter to nine', it's usually put 差一刻九点, 差十五分钟九点，还有十五分钟九点， 还有一刻钟九点

In the casual situations, I would say like 九点十五, 九点零四， 八点二十， 四点半(never say 四点半分)， 三点四十，两点（整）。

九点一刻 or 九点三刻 sounds a little bit formal than 九点十五 or 九点四十五.

分 is omitted most of time and 九点十五分 sounds a bit formal, for you are trying to be accurate.

But if you add 秒, you should not omit anything, like 九点十五分三十六秒, not 九点十五 三十六.

As for 'a quarter to nine', it's usually put 差一刻九点, 差十五分钟九点，还有十五分钟九点， 还有一刻钟九点