How did you solved it?

The first phot is 1/10sec and the 2nd photo is 1/8sec.
Could be due to handshake problem.

The first phot is 1/10sec and the 2nd photo is 1/8sec. That means the shutter speed is too slow.
If you kid move a little bit, then you have a blur photo.

Maybe you try taking a photo of a vase and see if it is still blur.
How about taking photos outdoor? Are they sharp?

Outdoor means under the sun.
Just step outside your house and take a few photos on the flower or your car also can.

The last photo looks better the the earlier two.
Noticed the shutter speed is faster at 1/20sec and the ISO is at 64.
The earlier two photos have slower shutter speed and the ISO was at 200. Probably these factors affect the poor result.

Your outdoor photos look quite good.
Can take one that is as close as your kids photo?
The distance is about 5ft.

The earlier indoor photos were most likely caused by slow shutter speed and high ISO.

The leaves are very distracting. Cannot comment.

When you take your kids to the taman, take some photos of them and compare to your earlier ones.
I am sure the outdoor ones will look great.

Yes, practice more and you will be expert very fast.

The C902 don't have that function. But can analyse from the photo to see what setting the camera used.
Some camera phone can select Auto, Low, Medium or High ISO.

I use the photo viewer call FastStone Image Viewer.
You can Google it. It is a freeware.
Install it and test it out.
Load a photo to view.
When you push the cursor to the 4 sides, top, bottom, left and right, it will show you the features.
When you push it to the right, you can see the exif of the photo. you can analyse the shutter speed, aperture used to take the photo.