The first sentence should be "On July 22, 2009, there was a solar eclipse in the sky." (In the sky is probably not necessary.) In the other sentences, you should then use "watch the solar eclipse," or simply "watch the eclipse" since it is already clear it was not a lunar eclipse.
As for the last sentence, I would rather write it as "We were lucky to watch the eclipse."
Since you are talking of a past event, the Simple Present is not the tense I would use. Alternatively, if you want to say that you were lucky to see the eclipse, and you still feel lucky, you can use the Perfect Present. Probably this is a better choice.
As side notes:
- Instead of my father told me to take sunglasses, I would say my father told me to take my sunglasses
- "At about 9:00 AM." is not a complete sentence, since it is missing the subject and the predicate; probably you meant to use the comma instead of the period
The text as I would write it is the following.
On July 22, 2009, there was a solar eclipse. In the morning, we got up early. After we had breakfast, my father told me to take my sunglasses to watch the eclipse on the playground. Many people arrived there early because it appears every 500 years. At about 9:00 AM, we saw the bright sky became gray. It also became much colder. After a while, the sky was bright again. We have been lucky to watch the eclipse.