Yes, but many schools have far fewer openings outside their main gateway years. Availability may depend on factors that are outside of a school’s control and hard to predict, like number of current students leaving. Competition is often greater for these years since the prospective student to available spot ratio for these non-gateway years is often worse than than it is for 6th and 9th grade entries.
Parents should be aware of this fact, especially if they know that their child will have no option but to transfer (if, for example, your family is moving). The best thing parents can do to combat this is ensure that their students have the strongest applications possible, including high ISEE scores and strong extracurriculars.