The number at the far right of the 550D viewfinder is the maximum burst indicator: how many shots the camera can take continuously before the buffer fills and shooting slows or stops temporarily.

If it shows 9, that doesn’t necessarily mean the limit is exactly 9 every time—the display typically won’t show values higher than 9. The actual burst capacity can change depending on settings such as RAW vs JPEG, ISO/noise reduction, white balance options, card speed, and even scene detail.

You can see it drop during continuous shooting, then rise again as the camera writes images to the memory card.

The dot is the focus confirmation indicator. When it lights, the camera believes autofocus has successfully locked focus on the subject.