Some of this is not a training problem, and treating it like one wastes time your dog may not have. If they are distressed when you leave, if they growl or guard their food, their toys or you, if they are frightened on the lead, or if anything about them changes suddenly at any age, contact your vet the same day. A tip from a website, ours included, is not the answer. If it cannot wait, contact your nearest emergency vet now.
With a Whippet, watch their stamina and their eyes. Tiring sooner than usual, lying down on walks, a faint, or fast breathing while they sleep can come from the heart, and an irregular heartbeat is a risk for Whippets from puppyhood. Bumping into furniture at dusk or hesitating on stairs can be the start of Progressive Retinal Atrophy (PRA, gradual loss of sight). Both are easy to put down to the heat or to age. Tell your vet early, because those months matter. Bloat (GDV, a twisted stomach) is most common in large, deep-chested dogs, so skip walks and hard play shortly before and after meals. A swollen, tight belly, retching with nothing coming up, sudden restlessness or drooling is an emergency: contact your vet now.
They'll keep running to whatever you wave. If they stop running to it, tell your vet.