From 9.9 version of theme, woocommerce grid has svg icon instead icon font. What if you want to change icon?
Use next
.woo_grid_compact .woo_loop_btn svg{display:none}
.woo_grid_compact .woo_loop_btn:before{font-family: rhicons; content: "\f002"; font-size: 20px;}
instead f002 you can use any other code which you can copy from RHIcons site. Please, note, that you must keep \ symbol.
you can place this in theme options – general options – custom css