There are $9$ cards with the numbers $1, 2, 3, 4, 5, 6, 7, 8$ and $9$. What is the largest number of these cards can be decomposed in a certain order in a row, so that in any two adjacent cards, one of the numbers is divided by the other?	
	
1. **Identify the constraints**: We need to arrange the cards such that for any two adjacent cards, one number is divisible by the other. The numbers on the cards are \(1, 2, 3, 4, 5, 6, 7, 8, 9\).

2. **Analyze divisibility**:
   - \(1\) divides all numbers.
   - \(2\) divides \(4, 6, 8\).
   - \(3\) divides \(6, 9\).
   - \(4\) divides \(8\).
   - \(5\) does not divide any other number except itself.
   - \(6\) does not divide any other number except itself.
   - \(7\) does not divide any other number except itself.
   - \(8\) does not divide any other number except itself.
   - \(9\) does not divide any other number except itself.

3. **Identify problematic numbers**: 
   - \(5\) and \(7\) are problematic because they do not divide any other number except themselves and are not divisible by any number other than \(1\).

4. **Construct a sequence**:
   - We can place \(1\) next to any number because \(1\) divides all numbers.
   - To maximize the number of cards, we need to place \(5\) and \(7\) at the ends of the sequence with \(1\) next to them.

5. **Formulate a sequence**:
   - Place \(5\) and \(7\) at the ends with \(1\) next to them: \(5, 1, \ldots, 1, 7\).
   - Use the remaining numbers to form a sequence that satisfies the divisibility condition: \(8, 4, 2, 6, 3, 9\).

6. **Verify the sequence**:
   - \(5, 1, 8, 4, 2, 6, 3, 9, 1, 7\) is a valid sequence.
   - However, we need to remove one number to fit the constraint of using only 8 cards.

7. **Remove one number**:
   - Remove \(5\) or \(7\) to get a sequence of 8 cards.
   - Example sequence: \(1, 8, 4, 2, 6, 3, 9, 1\).

8. **Verify the final sequence**:
   - \(1\) divides \(8\).
   - \(8\) divides \(4\).
   - \(4\) divides \(2\).
   - \(2\) divides \(6\).
   - \(6\) divides \(3\).
   - \(3\) divides \(9\).
   - \(9\) divides \(1\).

Thus, the largest number of cards that can be arranged in a row such that in any two adjacent cards, one number is divisible by the other is \(8\).

The final answer is \(\boxed{8}\).