diff --git a/years/2025/src/day_9.rs b/years/2025/src/day_9.rs
--- a/years/2025/src/day_9.rs
+++ b/years/2025/src/day_9.rs
@@ -1,15 +1,82 @@
 use advent_core::{day_stuff, ex_for_day, Day};
+use utils::pos::Position;
 
 pub struct Day9;
 
 impl Day for Day9 {
-    day_stuff!(9, "", "");
+    day_stuff!(9, "50", "24", Vec<Position>);
+
+    fn part_1(input: Self::Input) -> Option<String> {
+        let ans = input
+            .iter()
+            .enumerate()
+            .flat_map(|(i, a)| {
+                input.iter().skip(i + 1).map(|b| {
+                    let p = (*b - *a).abs();
+                    (p.x + 1) * (p.y + 1)
+                })
+            })
+            .max()
+            .unwrap();
+
+        Some(ans.to_string())
+    }
+
+    fn part_2(mut input: Self::Input) -> Option<String> {
+        let mut max = 0;
+
+        input.push(*input.first().unwrap());
+
+        let lines = input.windows(2).map(|w| (w[0], w[1])).collect::<Vec<_>>();
+
+        for (i, a) in input.iter().enumerate() {
+            // println!("Start {} ({}/{})", *a, i + 1, input.len());
+            for b in input.iter().skip(i + 1) {
+                let p = (*b - *a).abs();
+                let area = (p.x + 1) * (p.y + 1);
+
+                if area > max {
+                    let check = lines.iter().any(|&l| {
+                        let (cons, b1, b2, c1, c2, r1, r2) = if l.0.x == l.1.x {
+                            (l.0.x, a.x, b.x, l.0.y, l.1.y, a.y, b.y)
+                        } else {
+                            (l.0.y, a.y, b.y, l.0.x, l.1.x, a.x, b.x)
+                        };
+
+                        let (lower_cons, upper_cons) = (b1.min(b2), b1.max(b2));
+                        let (line_range_lower, line_range_upper) = (c1.min(c2), c1.max(c2));
+                        let (rect_range_lower, rect_range_upper) = (r1.min(r2), r1.max(r2));
+
+                        let cons_in_range = cons > lower_cons && cons < upper_cons;
+                        let ranges_overlap = if line_range_lower < rect_range_lower {
+                            line_range_upper > rect_range_lower
+                        } else {
+                            rect_range_upper > line_range_lower
+                        };
+
+                        cons_in_range && ranges_overlap
+                    });
 
-    fn part_1(_input: Self::Input) -> Option<String> {
-        None
+                    if !check {
+                        max = area;
+                    }
+                }
+            }
+        }
+
+        Some(max.to_string())
     }
 
-    fn part_2(_input: Self::Input) -> Option<String> {
-        None
+    fn parse_input(input: &str) -> Self::Input {
+        input
+            .lines()
+            .map(|l| {
+                let (x, y) = l.split_once(',').unwrap();
+                Position {
+                    x: x.parse().unwrap(),
+                    y: y.parse().unwrap(),
+                }
+            })
+            .collect()
     }
 }
diff --git a/years/2025/src/examples/day_9/1.txt b/years/2025/src/examples/day_9/1.txt
--- a/years/2025/src/examples/day_9/1.txt
+++ b/years/2025/src/examples/day_9/1.txt
@@ -0,0 +1,8 @@
+7,1
+11,1
+11,7
+9,7
+9,5
+2,5
+2,3
+7,3
diff --git a/years/2025/src/examples/day_9/2.txt b/years/2025/src/examples/day_9/2.txt
--- a/years/2025/src/examples/day_9/2.txt
+++ b/years/2025/src/examples/day_9/2.txt
@@ -0,0 +1,8 @@
+7,1
+11,1
+11,7
+9,7
+9,5
+2,5
+2,3
+7,3