If I was in a wreck while on company business in my personal vehicle, is my employer required to pay my deductible/damages?

Unfortunately, no--your employer would only be eligible to pay your deductible/damages if there had specifically been either 1) an agreement or contract between you and your employer requiring them to pay this; or 2) they had promised they would pay prior to you driving on business, and the only reason you drove your personal vehicle on business was this promise, and they were aware of that.