3行目　
the pet is a member → pets are part

4行目
pets → pet's

5行目
animal hospital → veterinary hospital / clinic, vet

5行目
in order for → for

6行目
pet service is → pet services are

7行目
hair cut, athretic park, and even funeral
→hair cuts, athletic parks, and funerals.

8行目
People my be use these services
→people could use these services (この文はなくて良い)

9行目
reason is more → reasons, more

9行目
are going to → will (文頭と統一)

同じ内容で書くなら、
以下で9割か満点もらえるはず、「はず」w
　I think more people will spend money on their pets in the future. I have two reasons to support this idea. First of all, many people recently see their pets as a family member. Therefor, people take good care of their pet's health by taking them to vets. The second reason is the increase of abundance in pet services. People can get their pets hair cuts and take them to parks for pets. Pets can even have their own funeral. For these reasons, I think more people will spend a lot of money on their pets in the future. (95単語)

100単語以内ならこんな感じ。

本当は自分の賛否の意見は最初か最後に一回言うだけでいいんだけど、終わり方がキモいと思ったり、文字数稼ぎのために後付けでもう一回言うのもあり。

質問等なんでも受け付けますので、聞きたいことがあれば教えてくださいねー！