9 students, 9 clues, 1 solution

Question

There were 24 students in a science class. As a challenge, the teacher pulled 9 of those kids, and told them they needed to order themselves in a specific way, but not tell anyone exactly why they chose that way. Each student was allowed to give only one hint about their position. The reason the students were ordered needed to be related (i.e. one student's reasoning couldn't be the number of buttons on a phone, while another's was the atomic number for helium).

After some discussion, they get into this order. Here are their clues:

Student 1: "I am .8 weaker than my half"
Student 2: "I'm often laughed at"
Student 3: "I am the hardest to escape compared to my neighbors"
Student 4: "I am 6/9 on another scale"
Student 5: "I am 2,095"
Student 6: "To escape, go to 10/2"
Student 7: "I am in second place"
Student 8: "332.6 f"
Student 9: "I am the richest, as far as we know"

What does each student correlate to?
Why are they in this order?

If an answer cannot be found, a random student will be chosen to give another clue.

Edit for clarification: The students each correlate to something. Their clues should be used to figure out what each student is. After knowing what they are, it must be figured out why they are in the order that they are in. The given order is the correct.

Answer 1

I'm thinking the teacher was feeling a bit frustrated and wanted to sort the students by how dense they are.

This would fit if the students were

Student 1: "I am .8 weaker than my half"

Saturn, planet number 6 from sun, has a gravitational pull (expressed by the gravitational acceleration at the theoretical surface level) of $9.0 \text{ m/s}^2$ which is .8 units weaker than the 9.8 of planet number 3 (half of 6), Earth. (Average density: $\mathbf{687} \text{ kg/m}^3$)

Student 2: "I'm often laughed at"

Uranus, laughed at, because he's always the butt of the joke. (Average density: $\mathbf{1271} \text{ kg/m}^3$)

Student 3: "I am the hardest to escape compared to my neighbors"

Jupiter has a higher escape velocity than either Mars or Saturn. (Or any other planet, for that matter.) (Average density: $\mathbf{1326} \text{ kg/m}^3$)

Student 4: "I am 6/9 on another scale"

Neptune (clue unsolved, but surely there's some scale that fits. In the comments @Stiv very sensibly suggests "6th smallest in diameter among this particular group of students".) (Average density: $\mathbf{1638} \text{ kg/m}^3$)

Student 5: "I am 2,095"

Pluto is not actually a planet anymore. (Average density: $\mathbf{2095} \text{ kg/m}^3$)

Student 6: "To escape, go to 10/2"

Mars has an escape velocity of $5.0 \text{ km/s}$. (Average density: $\mathbf{3933} \text{ kg/m}^3$)

Student 7: "I am in second place"

Venus is the second planet from the Sun. (Average density: $\mathbf{5243} \text{ kg/m}^3$)

Student 8: "332.6 f"

Mercury's surface temperature varies wildly, but the "official guess as to the average" is somewhere in the vicinity of 440K, which corresponds to 332 degrees Fahrenheit if we want to include too many significant digits. (Average density: $\mathbf{5427} \text{ kg/m}^3$)

Student 9: "I am the richest, as far as we know"

Earth is the only planet whose inhabitants have invented money. (As far as we know.) (Average density: $\mathbf{5514} \text{ kg/m}^3$)

Main data source:

Planetary Fact Sheet from the NASA Space Science Data Coordinated Archive.