Yes you can. If it’s an outdoor type spruce tree (Picea species), you can grow it in a pot indoors, but in the winter it will need a resting period in a cold (below freezing) place with some natural light. Spruce and pine trees (except semi-tropical conifers like Norfolk Island Pines) need a winter rest period where they slow down in growth. If you keep them in the warm indoors all year round, they will eventually “burn out” and die. You can take the potted tree and bury it in the ground in late fall just before freezing, and give it a good watering before the snow hits. This is practical if the pot is small enough to be buried. Don’t worry, spruces and pines are very winter hardy——the soil around them should be an “ice ball” throughout the winter. If you leave the pot outside without burying it, there is a chance the tree will die because the roots need protection from rapidly changing temperatures. But I have left small potted white spruces and pines outside all winter where I live without burying them, and they have survived, especially white and Colorado spruces (Picea glauca and Picea pungens). And I live in north central Canada where the winter temperature dips to minus 35 sometimes. If you have a Norfolk Island Pine, you don’t have to worry about giving them a winter rest. They do well indoors all year round. Other “Christmas trees” like the normal spruces and pines do not do too well in the dry warm air of most homes. A cool lighted area inside the house would do, but again, they need the winter rest, and indoors, they need a little cool humidity too. Your balcony would do nicely for the time being, and the tree can stay outdoors all winter as long as it doesn’t get too cold. If it does, you should give it a good watering so that the soil in the pot freezes——evergreens need the moisture all winter, even though the soil is frozen solid. Unlike deciduous trees, they do not go completely dormant in the winter, but they still have to rest.