Nine month old wheezes. Is it asthma?

If it justt started recently and corresponded with the start of spring that would seem to point to allergies to something airborn like pollen, but it could also be the onset of asthma or something else. You should discuss it with your child's doctor and to whatever testing they recommend to find out what the issue is. Don't mess around with things that effect a baby's ability to breathe. Better safe than sorry.