How do I change the hover (focus) color of admin bar from frontend?

switch your hook to ['admin_bar_menu'] and make things !important.

add_action( 'admin_bar_menu', 'change_bar_color1' );

function change_bar_color1() {

    ?>

    <style>
        #wpadminbar .ab-empty-item, #wpadminbar a.ab-item, #wpadminbar > #wp-toolbar span.ab-label, #wpadminbar > #wp-toolbar span.noticon {
            color: #FFFFFF !important;
        }

        #wpadminbar {
            background: #ff6000 !important;
            border-top: 2px solid #000000;
            border-bottom: 2px solid #000000;
            border-left: 2px solid #ff6000;
            border-right: 2px solid #ff6000
        }

        #wpadminbar .quicklinks ul li a:hover {
            background: #ffffff
        }

        #wpadminbar .ab-top-menu > li.hover > .ab-item, #wpadminbar .ab-top-menu > li.menupop.hover > .ab-item, #wpadminbar .ab-top-menu > li:hover > .ab-item, #wpadminbar .ab-top-menu > li > .ab-item:focus, #wpadminbar-nojs .ab-top-menu > li.menupop:hover > .ab-item, #wpadminbar.nojq .quicklinks .ab-top-menu > li > .ab-item:focus {
            color: #fff !important;
            background: #ffa948 !important;
        }

        #wpadminbar .menupop .ab-sub-wrapper {
            background: #fc8805;
            border-bottom: 2px solid #ff6000;
            border-left: 2px solid #000000;
            border-right: 2px solid #000000
        }

        #wpadminbar .ab-submenu .ab-item, #wpadminbar .quicklinks .menupop ul li a, #wpadminbar .quicklinks .menupop.hover ul li a, #wpadminbar-nojs .quicklinks .menupop:hover ul li a {
            color: #000000 !important;
        }

        #wpadminbar .menupop .menupop > .ab-item:hover:before, #wpadminbar .quicklinks .menupop ul li a:focus, #wpadminbar .quicklinks .menupop ul li a:focus strong, #wpadminbar .quicklinks .menupop ul li a:hover, #wpadminbar .quicklinks .menupop ul li a:hover strong, #wpadminbar .quicklinks .menupop.hover ul li a:focus, #wpadminbar .quicklinks .menupop.hover ul li a:hover, #wpadminbar .quicklinks li a:hover .blavatar, #wpadminbar li .ab-item:focus:before, #wpadminbar li a:focus .ab-icon:before, #wpadminbar li.hover .ab-icon:before, #wpadminbar li.hover .ab-item:after, #wpadminbar li.hover .ab-item:before, #wpadminbar li:hover #adminbarsearch:before, #wpadminbar li:hover .ab-icon:before, #wpadminbar li:hover .ab-item:after, #wpadminbar li:hover .ab-item:before, #wpadminbar.nojs .quicklinks .menupop:hover ul li a:focus, #wpadminbar.nojs .quicklinks .menupop:hover ul li a:hover {
            color: #ff0000 !important;
        }

        #wpadminbar .quicklinks .menupop ul.ab-sub-secondary, #wpadminbar .quicklinks .menupop ul.ab-sub-secondary .ab-submenu {
            background: #ffb45f !important;
        }

    </style>

    <?php
}