I have change all columns width in my case as
worksheet.Columns[1].ColumnWidth = 7;
worksheet.Columns[2].ColumnWidth = 15;
worksheet.Columns[3].ColumnWidth = 15;
worksheet.Columns[4].ColumnWidth = 15;
worksheet.Columns[5].ColumnWidth = 18;
worksheet.Columns[6].ColumnWidth = 8;
worksheet.Columns[7].ColumnWidth = 13;
worksheet.Columns[8].ColumnWidth = 17;
worksheet.Columns[9].ColumnWidth = 17;
Note: Columns in worksheet start with 1 not from 0 as in Arrary.