Can a boot/cast help fix anterior ankle impingement? i cheer so avoiding activity is not an option. i feel like it would help my situation

See below: A boot cast will immobilize your foot and ankle taking pressure off of the area but it will make it difficult to continue strenuous activity. The key is reduced activity and find the cause for the impingement.

Ankle pain: Anterior ankle impingement is usually due to formation of bone spurs, commonly seen w/ arthritis but can also occur in athletes - soccer players, other sports involving impact on foot. Pain is in front of ankle. Properly fitting splints/lace up boot may help, ice/heat, stretching exercises, PT anti-inflammatory meds such as ibuprofen may help. If not improving then see an orthopedist

You could always: Try it if you feel it will help. Usually with an impingement syndrome there is something present which is blocking motion and until that is removed you will limit range of motion. The boot may make it feel good in that it limits motion further but ultimately until you remove the impingement I don't think it gets better.