In a joint-stock limited liability company, one person holds 90% of the shares, one person holds 10%, and 10% of the shares can be a company legal person?

Yes, as long as this person is the chairman or executive director of the company. If another shareholder agrees to be an executive director or chairman, then this person will naturally become the legal representative of the company. Because our country's laws stipulate that the legal representative of the company, unless otherwise stipulated in the articles of association, the chairman or executive director is the legal representative.