Please do not "spray" these shrubs. You are harming birds, bees, butterflies & all kinds of other beneficial insects. The insecticide is far more harmful than whatever "pest" you are trying to eradicate. If you have a plant that regularly becomes infested, it's a sign the plant does not belong in whatever place--or possibly region--it is planted in. Even so-called organic insecticidal soaps kill honey bees & butterflies. There is no such thing as a "safe" garden chemical.

I give up, what tree is it?

It is a spruce and yes you can trim the bottom. We have many and unless it is a dwarf they grow tall and just keep getting wider every year. They also look kind of neat with the bottom taken out IMO

Garden Centers are not all alike - many with national distribution sell invasive plants! You can narrow your choices using online charts, photos, plant characteristics, and some of your location criteria. First...are you hoping for an evergreen, fruit, flowers, fall color? Is the planting site indoors or Out? in a large pot, or in the ground? Is there a height or other limitation? As you isolate a list, consider, What is your Zone? Is your shortlist compatible for winter/hot summer conditions? Look at your planting site, soil type, drainage and if you can manage the attention/alterations which may be needed to help your plant adjust to your site. Some considerations before the final decisions might be: water source/needs. Would a shrub be better for your goals? What mulch to choose? Can you underplant the tree with a group of beneficial plants for soil health? Enjoy the journey. Perennial plants are worth it!