9. (3 points) Cut a rectangular cardboard that is 90 cm long and 42 cm wide into small square pieces with integer side lengths and equal areas, without any leftover. The minimum number of squares that can be cut is $\qquad$, and the total perimeter of all the square pieces in this cutting method is $\qquad$ cm.
【Analysis】According to the problem, to cut the least number of pieces, the side length of the small squares should be the largest. To ensure there is no remainder in length and width, we actually need to find the greatest common divisor (GCD) of 90 and 42, and use this GCD as the side length of the small squares. Then, calculate the area of the rectangular paper and the area of the small square pieces, and divide the area of the rectangle by the area of the small square to find the minimum number of pieces. Calculate the perimeter of one square and multiply it by the number of pieces to find the total perimeter of all the square pieces.

【Solution】Solution: The greatest common divisor of 90 and 42 is 6, which means the side length of the small squares is 6 cm. The number of pieces that can be cut along the length: $90 \div 6 = 15$ (pieces),

The number of rows that can be cut along the width: $42 \div 6 = 7$ (rows),
The total number of pieces: $15 \times 7 = 105$ (pieces);
Total perimeter: $6 \times 4 \times 105 = 2520$ (cm);
Answer: At least 105 pieces need to be cut, and the total perimeter of all the square pieces cut in this way is 2520 cm; Therefore, the answers are: 105, 2520.