Unfortunately, slow cooker manufacturers do not include delayed-start timers among their features. This is strictly a safety issue: if you have food sitting on your countertop for hours before the cooker turns on, it's the ideal breeding ground for bacteria that could lead to illness, particularly if you've got raw meat in the cooker. But this doesn't mean a slow cooker can't work for you. Since stewy slow-cooked meals freeze beautifully, try doing your cooking on the weekends when you'll be home when cooking finishes. Cool the food completely and package it in a vacuum-seal bag or a freezer-safe container. Freeze or refrigerate the meal until you're ready to eat it, then you can quickly heat it on the stove.
Another option that might work for you is a slow cooker that has a timer in which the cooker will switch to a "keep warm" setting when the cooking time is reached. This will keep your food at a safe heat level for another hour or two, until it's time for dinner. Try the Crock-Pot eLume Slow Cooker.